OS and Software Troubleshooting

OS and Software Troubleshooting

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Software problems are more common than hardware problems. The good news is they are usually fixable without replacing parts. The key is identifying whether the issue is the OS, an application, a driver, or malware.

Scenario 1: Blue Screen of Death (BSOD)

The Blue Screen of Death means Windows encountered a critical error and stopped to prevent data corruption. The stop code tells you what happened.

Common stop codes:

• IRQL_NOT_LESS_OR_EQUAL (0x0A): Bad driver or faulty RAM. Update drivers, run MemTest86.

• PAGE_FAULT_IN_NONPAGED_AREA (0x50): Bad RAM or bad driver. Test RAM, check recent driver updates.

• INACCESSIBLE_BOOT_DEVICE (0x7B): Storage driver failure or failing drive. Run chkdsk, check SATA connections.

• SYSTEM_SERVICE_EXCEPTION (0x3B): Driver or system service crash. Update drivers, run sfc /scannow.

• CRITICAL_PROCESS_DIED (0xEF): Essential Windows process stopped. May indicate system file corruption. Run sfc and DISM.

• CLOCK_WATCHDOG_TIMEOUT (0x101): CPU or motherboard issue. Update BIOS, check cooling.

Troubleshooting:

1. Note the stop code and any file mentioned (e.g., nvlddmkm.sys = NVIDIA driver)

2. Check Event Viewer > Windows Logs > System for errors at the same time

3. Was there a recent update? Roll it back: Settings > Windows Update > Update History > Uninstall

4. Was there a new driver installed? Roll back in Device Manager > Properties > Driver tab

5. Run sfc /scannow — repairs corrupt system files

6. Run dism /online /cleanup-image /restorehealth — repairs Windows image

7. Run Memory Diagnostic or MemTest86 — check for RAM errors

8. Boot in Safe Mode — if BSOD doesn't occur, it's a driver or startup program

Scenario 2: Application Crashing or Not Responding

Symptoms: App freezes, closes unexpectedly, 'Not Responding' in title bar, crash report dialogs.

Troubleshooting:

1. Check for updates — both the app and Windows itself

2. Run as Administrator — some apps need elevated permissions

3. Compatibility mode — right-click > Properties > Compatibility > Run in compatibility mode for older Windows versions

4. Clear app cache and temp files — check %temp% and AppData folders

5. Reinstall the application — uninstall completely, then reinstall fresh

6. Check Event Viewer > Windows Logs > Application for crash details

7. Run in Safe Mode — if the app works in Safe Mode, another program is conflicting

8. Check for conflicting software — antivirus, other apps that hook into the same functions

9. Check disk space — low disk space (under 10% free) causes crashes

Scenario 3: Slow Computer Performance

Symptoms: Slow boot, programs take long to open, fan running constantly, system feels sluggish.

Troubleshooting:

1. Open Task Manager (Ctrl+Shift+Esc) — check CPU, RAM, and disk usage

2. Startup programs: Task Manager > Startup tab — disable unnecessary startup apps

3. Check disk type: is it HDD or SSD? If HDD, upgrading to SSD is the #1 performance fix

4. Check RAM: if RAM is at 90%+, add more RAM (8GB minimum, 16GB recommended)

5. Run disk cleanup: cleanmgr — remove temp files, old updates, recycle bin

6. Defragment HDD: dfrgui (NEVER defrag SSDs — they don't need it and it reduces lifespan)

7. Check for malware: full scan with Windows Defender or Malwarebytes

8. Check background processes: if CPU is at 100%, identify which process and investigate

9. Disable unnecessary services: services.msc — be careful, only disable what you understand

10. Reset power plan to Balanced or High Performance

Quick wins: Disable startup programs, upgrade to SSD, add RAM, run disk cleanup. These four actions solve 80% of slow computer complaints.

Scenario 4: Network Connectivity Issues

Symptoms: Can't access internet, can't reach network shares, intermittent connectivity.

Troubleshooting:

1. Check the physical cable — swap with a known-good cable

2. Check the network icon in system tray — yellow triangle = limited, red X = no connection

3. Run ipconfig /all — check IP, gateway, DNS

4. If 169.254.x.x — DHCP failed: ipconfig /release then /renew, or check DHCP server

5. Ping gateway: ping 192.168.1.1 — if fails, local network issue

6. Ping 8.8.8.8 — if fails but gateway works, internet routing issue

7. Ping google.com — if fails but 8.8.8.8 works, DNS issue: try nslookup, change DNS to 8.8.8.8

8. Check proxy settings: Internet Options > Connections > LAN Settings

9. Flush DNS: ipconfig /flushdns

10. Reset TCP/IP: netsh int ip reset, netsh winsock reset — requires reboot

11. Check firewall: is it blocking the connection? Try temporarily disabling to test

Scenario 5: Printer Not Working

Symptoms: Printer offline, documents stuck in queue, can't find printer on network.

Troubleshooting:

1. Check printer power and network connection

2. Clear print queue: Services > Print Spooler > Stop, delete files in C:\Windows\System32\spool\PRINTERS\*, Start service

3. Check if printer is online in Settings > Devices > Printers

4. Run Windows troubleshooter: Settings > Devices > Printers > Run troubleshooter

5. Remove and re-add the printer

6. Update or reinstall the printer driver from the manufacturer's website

7. For network printers: verify IP address hasn't changed, check printer port settings

8. Test direct USB connection — if USB works but network doesn't, it's a network issue

9. Check printer firmware — update from manufacturer's website

Scenario 6: Windows Won't Boot

Symptoms: Stuck on boot logo, 'Preparing Automatic Repair' loop, 'Your PC did not start correctly'.

Troubleshooting:

1. Try Safe Mode: hold Shift + click Restart > Troubleshoot > Advanced Options > Startup Settings > F4

2. If Safe Mode works: disable startup programs and services, then reboot normally

3. Run startup repair: Advanced Options > Startup Repair — Windows attempts automatic fix

4. Run chkdsk: Advanced Options > Command Prompt > chkdsk C: /f /r

5. Run sfc /scannow from Command Prompt

6. Run bootrec: bootrec /fixmbr, bootrec /fixboot, bootrec /rebuildbcd — fixes boot configuration

7. System Restore: Advanced Options > System Restore — pick a restore point before the problem

8. If all fails: reset Windows — Keep my files option preserves user data

Free Software Diagnostic Tools

Event Viewer (eventvwr.msc): Windows system, application, and security logs. Essential for diagnosing BSODs and app crashes.

Reliability Monitor (perfmon /rel): Visual timeline of crashes, updates, and problems.

Autoruns (Sysinternals): Shows everything that starts with Windows. More thorough than Task Manager startup tab.

Process Explorer (Sysinternals): Advanced task manager showing process trees, DLLs, and handles.

Malwarebytes Free: Malware scanner. Second opinion after Windows Defender.

AdwCleaner: Removes adware, toolbars, and PUPs (Potentially Unwanted Programs).

Key Takeaways

• BSOD stop codes tell you what went wrong — Google the code for specific solutions

• sfc /scannow and DISM are the primary Windows repair commands

• Upgrading HDD to SSD fixes 80% of slow computer complaints

• Network troubleshooting follows the ping chain: loopback > gateway > internet > DNS

• Clearing the print spooler fixes most printer queue issues

• Use Event Viewer and Reliability Monitor to diagnose recurring problems

Common Questions

Q: Should I defragment my SSD?
A: No. SSDs don't need defragmentation. Windows automatically optimizes SSDs with TRIM. Defragmenting an SSD reduces its lifespan.

Q: How do I fix 'Your PC did not start correctly'?
A> Try Startup Repair first, then System Restore, then chkdsk, then reset Windows keeping files.