IT Troubleshooting Hub

Check if other devices on the same network have internet

Restart your router and modem — unplug power for 30 seconds

On Windows: Run `ipconfig /release` then `ipconfig /renew` in Command Prompt (Admin)

Flush DNS: `ipconfig /flushdns` (Windows) or `sudo dscacheutil -flushcache` (macOS)

Reset TCP/IP stack: `netsh int ip reset` (Windows, run as Admin, then restart)

Disable and re-enable your network adapter in Device Manager

Check if your ISP has an outage at their status page or downdetector.com

Try connecting with an Ethernet cable to rule out WiFi issues

Update WiFi adapter driver from Device Manager → Network Adapters → right-click → Update driver

Disable WiFi adapter power saving: Device Manager → WiFi adapter → Properties → Power Management → uncheck "Allow computer to turn off device to save power"

Change WiFi channel on router — use a WiFi analyzer app to find least congested channel

Switch from 2.4GHz to 5GHz band (or vice versa) in router settings

Set DNS to 8.8.8.8 / 8.8.4.4 (Google) or 1.1.1.1 (Cloudflare)

Forget the network and reconnect: Settings → WiFi → Forget → Reconnect

If on Windows 11: run Network Troubleshooter (Settings → System → Troubleshoot)

Check router logs for DHCP lease conflicts

Flush DNS cache: `ipconfig /flushdns` (Windows) or `sudo killall -HUP mDNSResponder` (macOS)

Change DNS servers: Control Panel → Network Adapter Properties → IPv4 → use 1.1.1.1 / 1.0.0.1 (Cloudflare) or 8.8.8.8 / 8.8.4.4 (Google)

Test DNS resolution: open CMD and run `nslookup google.com`

If nslookup works, the issue is browser-specific — clear browser cache and DNS in chrome://net-internals/#dns

Check your hosts file: `C:\Windows\System32\drivers\etc\hosts` — remove suspicious entries

Disable IPv6 if DNS is failing on dual-stack: adapter properties → uncheck IPv6

On Linux: `sudo systemctl restart systemd-resolved` or edit `/etc/resolv.conf`

This is a DNS resolution issue — your DNS server is unreachable or misconfigured

Check DNS settings: `ipconfig /all` and look for "DNS Servers"

Try manually pinging a known DNS server: `ping 8.8.8.8` — if this works, DNS is the issue

Change DNS to 8.8.8.8: adapter settings → IPv4 → Preferred DNS: 8.8.8.8

Test with: `nslookup google.com 8.8.8.8` — if this works, your router DNS is broken

On corporate networks: check if the DNS suffix is set. Run `ipconfig /all` and check "DNS Suffix Search List"

Restart DNS client service: `net stop dnscache && net start dnscache`

Check Task Manager (Ctrl+Shift+Esc) — identify processes with high CPU/RAM/Disk usage

Disable startup programs: Task Manager → Startup → Disable unnecessary apps

Run Disk Cleanup: type "Disk Cleanup" in search, select C: drive, clean system files

Defragment HDD (NOT SSD): search "Defragment drives" — run on HDDs only

Check for malware: run Windows Defender full scan or Malwarebytes (free)

Adjust visual effects: search "Adjust the appearance" → Adjust for best performance

Check for Windows Update stuck downloads hogging CPU

If high disk usage: disable Windows Search indexing temporarily and Windows Superfetch (SysMain service)

Increase virtual memory if RAM is maxed: System → Advanced → Performance Settings → Virtual Memory

Consider upgrading RAM (if 4GB or less) or replacing HDD with an SSD

Note the STOP code (e.g., IRQL_NOT_LESS_OR_EQUAL, MEMORY_MANAGEMENT) — search it for specific fixes

Check for recent driver updates: a new GPU or network driver often causes BSODs — roll back in Device Manager

Run Windows Memory Diagnostic: search "Windows Memory Diagnostic" — restart and test RAM

Run SFC scan: open CMD as Admin → `sfc /scannow` — waits for scan to complete

Run DISM: `DISM /Online /Cleanup-Image /RestoreHealth` in Admin CMD

Check event viewer: search "Event Viewer" → Windows Logs → System — look for Critical errors before the crash

Test RAM sticks individually — remove one at a time and see if crashes stop

Check hard drive health: download CrystalDiskInfo (free) — look for "Caution" or "Bad" status

If after Windows Update: uninstall recent update from Settings → Windows Update → View Update History → Uninstall

Check power connections — reseat the 24-pin ATX and 8-pin CPU power connectors

Try with one RAM stick — remove all RAM, reseat one stick in the correct slot (check manual)

Clear CMOS: locate CMOS battery on motherboard, remove for 30 seconds, reinsert (clears BIOS settings)

Check if GPU is seated properly — remove and reinsert firmly

Connect monitor directly to GPU, NOT motherboard (if you have a discrete GPU)

Listen for beep codes — look up your motherboard's beep code guide

Unplug all non-essential devices (HDDs, optical drives, extra RAM) — boot with minimum hardware

Test with a known-working PSU if available — bad PSU is a common cause

If POST then Windows fails: boot from Windows USB and run Startup Repair

Open Task Manager → CPU column → click to sort descending — identify the top CPU consumer

Common culprit: "Windows Update" (`TiWorker.exe`, `WaaSMedicSVC`) — wait for it to finish or pause Windows Updates

Antivirus scan in background: temporarily disable and check if CPU drops

Malware: run Malwarebytes free scan — cryptomining malware causes 100% CPU

WSAPPX high CPU: restart "Windows Update" service in services.msc

svchost.exe high CPU: `net stop wuauserv` in Admin CMD to temporarily stop Windows Update

Check thermals: download HWiNFO64 — if CPU is thermal throttling (95°C+), clean dust from cooler, reapply thermal paste

Disable Cortana indexing: in Task Manager find SearchIndexer.exe or SearchHost.exe and pause/disable

Check if SSH server is running: `sudo systemctl status sshd` or `sudo service ssh status`

Start SSH service if stopped: `sudo systemctl start sshd` or `sudo service ssh start`

Check if port 22 is open: `sudo netstat -tlnp | grep 22` or `sudo ss -tlnp | grep 22`

Check firewall: `sudo ufw status` (Ubuntu) or `sudo firewall-cmd --list-all` (CentOS)

Allow SSH through firewall: `sudo ufw allow ssh` or `sudo firewall-cmd --add-service=ssh --permanent`

Verify the correct SSH port in config: `grep Port /etc/ssh/sshd_config`

If port changed, connect with: `ssh -p 2222 user@host`

Check authorized_keys permissions: `chmod 700 ~/.ssh && chmod 600 ~/.ssh/authorized_keys`

Check disk usage: `df -h` to see which partition is full

Find what is using space: `du -sh /* 2>/dev/null | sort -rh | head -20`

Check /var/log: `du -sh /var/log/*` — clear old logs: `sudo journalctl --vacuum-time=7d`

Clean package cache: `sudo apt autoremove && sudo apt autoclean` (Debian/Ubuntu)

Remove old kernels: `sudo apt autoremove --purge` (keeps current kernel only)

Find large files: `find / -type f -size +100M -not -path "/proc/*" 2>/dev/null`

Check and delete old Docker images: `docker system prune -af` (if Docker installed)

Clear /tmp: `sudo rm -rf /tmp/*` (safe to clear)

Understand the error: `ls -la filename` to see current permissions and owner

If you need to execute a script: `chmod +x script.sh` then `./script.sh`

If accessing another user's file: use `sudo` before the command (if you have sudo access)

If a service can't access a file: check owner (`ls -la`) and group, change with `chown user:group file`

Numeric permissions: `chmod 755 file` (owner: rwx, group: r-x, others: r-x)

Make a file world-readable: `chmod 644 file.txt`

Recursively fix permissions: `chmod -R 755 /var/www/html` (dangerous — use carefully)

Check SELinux context if on CentOS/RHEL: `ls -Z filename` and use `restorecon -v filename`

Try a different cable (HDMI, DisplayPort, VGA) — cables can fail

Connect to a different port on the GPU or monitor

If GPU is installed: connect to GPU ports, not motherboard ports

Check if monitor is on the right input source (HDMI 1 vs HDMI 2 vs DisplayPort)

Reseat the GPU — turn off PC, unplug, press GPU firmly into PCIe slot, reconnect power

Try connecting a different monitor to rule out monitor failure

Boot into BIOS to confirm GPU is outputting signal

If integrated graphics: check BIOS settings — ensure iGPU is enabled if using motherboard display out

Set printer Online: right-click printer in Devices & Printers → See what's printing → Printer menu → uncheck "Use Printer Offline"

Clear print queue: stop Print Spooler service → delete files in `C:\Windows\System32\spool\PRINTERS\` → restart service

In Command Prompt (Admin): `net stop spooler`, then `del /Q /F /S "%systemroot%\System32\spool\PRINTERS\*.*"`, then `net start spooler`

Reinstall printer driver: Devices & Printers → right-click → Remove device → re-add via Add a printer

Check USB/network connection — try a different USB port

Run Windows Printer Troubleshooter: Settings → System → Troubleshoot → Other troubleshooters → Printer

Check ink/toner levels from manufacturer software

Run a speed test at fast.com or speedtest.net — test both WiFi and Ethernet

If Ethernet is fast but WiFi is slow: WiFi interference or distance issue

Change WiFi channel — use a free WiFi analyzer (e.g., inSSIDer) to find the least congested channel

Reboot router and modem — unplug both for 60 seconds

Check if another device or app is consuming bandwidth — use router admin panel to see

Check for ISP throttling: try a VPN briefly — if speed improves, ISP is throttling

Update router firmware from router admin panel

Move router to a central, elevated location — avoid placing near microwaves or thick walls

If speeds are consistently far below plan: call ISP — request a line test

Open Task Manager → Memory column → sort descending — find which apps use most RAM

Close unused browser tabs — Chrome/Edge can use 1GB+ with many tabs

Disable startup programs: Task Manager → Startup → disable heavy apps

Identify RAM-hogging services: `services.msc` — disable unneeded services (be careful)

Adjust virtual memory: System Properties → Advanced → Performance Settings → Virtual Memory → Custom size (1.5x RAM for initial, 3x for maximum)

Check for memory leaks: if RAM grows over time without new apps, there's a leak

Disable Superfetch/SysMain if you have an SSD (services.msc → SysMain → disable)

Consider upgrading RAM — 8GB minimum for Windows 11 smooth operation, 16GB recommended

Check Settings → Battery → Battery usage — find which app is consuming the most power

Look specifically for an app stuck "Awake" or with unusually high "Background usage" — this is the most common cause

Disable battery-heavy background refresh: Settings → Apps → [app] → Battery → Restrict background usage

Check Settings → Battery → Adaptive Battery is enabled (Android 9+)

Reduce screen timeout and brightness — screen is typically the single largest battery consumer

Check for a pending Android system update — some updates specifically fix battery regressions from a prior release

If one specific app started draining battery suddenly after an update, check if a newer version is available or temporarily uninstall to confirm it's the cause

As a last resort, back up your data and try a factory reset — a corrupted battery stats file can cause inaccurate, exaggerated drain readings

Go to Settings → Storage to see exactly what's using space (apps, photos, cached data, "Other")

Clear app cache first, not app data: Settings → Apps → [app] → Storage → Clear Cache — this is reversible and safe

Use Google Photos' "Free up space" feature to remove photos already backed up to the cloud from local storage

Check Downloads folder — it accumulates files from browsers and apps that are rarely revisited

Uninstall unused apps: Settings → Apps → sort by size, remove anything unused for months

Move photos/videos to an SD card if your device supports expandable storage

Check WhatsApp/Telegram media folders specifically — auto-downloaded media accumulates silently and is a common large, forgotten storage consumer

Toggle Airplane Mode on for 10 seconds, then off — this resets the radio hardware state

Forget the network and reconnect: Settings → WiFi → long-press network → Forget → reconnect with password

Restart the router — an IP or DHCP lease conflict on the router side is a common cause of "connects but no internet"

Check Settings → WiFi → network is not set to a static IP with wrong values (should be DHCP/Automatic unless you configured it deliberately)

Reset network settings: Settings → System → Reset options → Reset WiFi, mobile & Bluetooth — this clears all saved networks and paired devices

Check for a pending system update — WiFi driver bugs are occasionally fixed in routine Android updates

If only one specific network fails while others work fine, the issue is almost certainly router-side, not the phone

Check Settings → Battery → Battery Health & Charging — if "Maximum Capacity" is well below 100%, the battery itself has degraded with age and use, which is a hardware wear issue, not a software bug

Check Settings → Battery for a per-app breakdown of usage over the last 24 hours/10 days — look for an app using disproportionate "Background Activity"

Check Settings → General → Background App Refresh and disable it for apps that don't need to update in the background

Reduce display brightness and enable Auto-Lock at a shorter interval (Settings → Display & Brightness → Auto-Lock)

Check for a pending iOS update — Apple has shipped specific battery-drain fixes in point releases before

Disable Always-On Display or reduce Lock Screen widget refresh if using an iPhone 14 Pro or later

If drain is sudden and severe after an update, note that this is a known pattern after major iOS releases while apps/background indexing settle — it often resolves within 24-48 hours

Inspect the Lightning/USB-C port for visible lint or debris — this is the single most common cause and is often fixed with a soft brush or toothpick (power off first)

Try a different cable and a different wall adapter — cables are the most common point of failure

Try charging from a wall outlet directly instead of a computer USB port, which often supplies less power

Restart the iPhone — hold the side button + volume button until the slider appears (or force-restart if unresponsive)

Check Settings → Battery for any battery-related warning message

If you see "This accessory may not be supported", the cable/adapter may be non-certified (not MFi-certified) — try an official Apple cable to confirm

If nothing charges it at all, including a known-working cable and outlet, this points to a hardware fault requiring an Apple Store/authorized repair visit

Force restart: iPhone 8 or later — quickly press Volume Up, quickly press Volume Down, then hold the Side button until the Apple logo appears

If force restart doesn't resolve it, connect to a computer with Finder (macOS Catalina+) or iTunes (Windows/older macOS) and put the device into Recovery Mode to attempt a restore

A restore via Recovery Mode will attempt to reinstall iOS while keeping your data if possible — but if the device was never backed up, understand that a full restore step later in the process may erase data

If the phone was recently jailbroken or had a beta iOS profile installed, this is a common, specific cause of boot loops

If Recovery Mode restore fails repeatedly, DFU (Device Firmware Update) mode is a deeper-level restore option, but should only be attempted following Apple's official steps exactly, as it fully reinstalls firmware

Persistent boot loops after a proper restore attempt typically indicate a hardware fault and need an Apple Store/authorized service visit

Check if WhatsApp is down for everyone, not just you, at a status page like downdetector.com — this rules out a local issue entirely

Confirm your internet connection actually works by loading a website in your browser first

Force-close WhatsApp completely and reopen it (not just switching away from it)

Check Settings → Apps → WhatsApp → Storage → Clear Cache (Android) — this does not delete your chats

Confirm your device's date and time are set to automatic — WhatsApp's encryption handshake can fail with an incorrect system clock

Check available storage space — WhatsApp can fail to send media (though usually not text) when storage is critically full

Update WhatsApp to the latest version from the Play Store/App Store — an outdated version can lose compatibility with current servers

As a last resort, log out is not available in WhatsApp the way it is in most apps — reinstalling preserves chat history only if you have a recent backup enabled

Close all Chrome windows/tabs completely and reopen — a single runaway tab (heavy JavaScript, a memory leak) can degrade the whole browser

Check chrome://net-internals/#dns and click "Clear host cache" if specific sites won't load

Clear browsing data: Settings → Privacy and security → Clear browsing data → Cached images and files (this doesn't delete bookmarks/passwords)

Disable extensions one by one: chrome://extensions → toggle off — a single misbehaving extension is a very common cause of crashes and slowdowns

Check chrome://version and confirm Chrome is on the current version — update via the three-dot menu → Help → About Google Chrome

Create a new Chrome profile (chrome://settings/people) to test whether the issue is profile-specific corruption rather than the browser itself

Check for a corrupted GPU/hardware acceleration issue: chrome://settings → System → toggle off "Use hardware acceleration when available" and restart

As a last resort, reset Chrome settings to default: Settings → Reset settings → Restore settings to their original defaults

Check OpenAI's official status page (status.openai.com) first — capacity and outage messages are almost always a server-side issue on their end, not your device or account

Refresh the page/app or force-close and reopen — a stuck WebSocket connection is a common, simple cause of a frozen or stalled response

Clear your browser cache and cookies specifically for chat.openai.com/chatgpt.com if using the web version

Try a different network (switch from WiFi to mobile data or vice versa) to rule out a local network/firewall block on the specific ports ChatGPT uses

Check if a browser extension (especially ad blockers or privacy/VPN extensions) is interfering — test in an incognito/private window with extensions disabled

If using the mobile app, confirm it's updated to the latest version from the App Store/Play Store

A message that stops generating mid-response mid-stream is typically a transient connection drop — regenerating the response usually resolves it immediately