CompTIA A+ Software Troubleshooting Summary

Safe Mode starts Windows with only the basic drivers and services it needs. If the problem goes away in Safe Mode, a driver or startup program is the likely cause, and the technician can remove or update it from there.

Wrong choices

• UEFI/BIOS setup: UEFI/BIOS setup changes firmware settings. It does not start Windows with fewer drivers.
• Airplane mode: Airplane mode only turns off wireless radios.
• Fast startup: Fast startup speeds up booting. It does not limit which drivers load.

Unwanted pop-ups and searches that go to strange sites are classic signs of adware or a browser hijacker. The technician should scan with updated anti-malware tools and check the browser for unknown extensions and changed settings.

Wrong choices

• Too little RAM: Low memory makes the PC slow, not redirect searches.
• A failing network card: A bad network card causes lost or slow connections, not pop-ups and redirected searches.
• A full printer queue: A printer queue has nothing to do with browser behavior.

Task Manager shows running programs and how much CPU, memory, disk, and network each one uses right now. Sorting by a column quickly shows which program is slowing the PC down.

Wrong choices

• Disk Management: Disk Management manages drives and partitions, not running programs.
• Device Manager: Device Manager shows hardware and drivers, not which programs are using resources.
• Event Viewer: Event Viewer shows logs of errors and events, not live CPU and memory use.

When a problem begins right after a driver update, the simplest fix is to go back to the driver that worked. In Device Manager, open the device's properties and choose Roll Back Driver on the Driver tab.

Wrong choices

• Turn off Windows Update permanently: Turning off updates leaves the PC unprotected and does not undo the bad driver.
• Replace the video card: The problems started with the new driver, so the card itself is not the first suspect.
• Reinstall Windows: Reinstalling Windows is far more work than needed when one driver change caused the problem.

Security certificates are valid only between certain dates. If the PC's clock is far off, every certificate can look expired or not yet valid. Fixing the date and time, often by syncing with an internet time server, usually clears the warnings.

Wrong choices

• The amount of free disk space: Low disk space does not cause certificate warnings.
• The browser, by reinstalling it: Reinstalling the browser is more work than needed. A wrong clock is a common and simple cause.
• The network card, by replacing it: A network card problem stops connections. It does not cause certificate warnings.

When only one app has a problem, start with the least disruptive fixes for that app: close it fully, clear its cache, check for a newer update, or uninstall and reinstall it. Resetting the whole phone is saved for when nothing else works.

Wrong choices

• Turn off Wi-Fi permanently: Turning off Wi-Fi does not fix an app that crashes on its own.
• Reset the phone to factory settings: A factory reset erases the whole phone and is a last resort when only one app has a problem.
• Replace the phone's battery: The battery does not cause one app to crash while others work.

System Restore returns Windows system files, drivers, installed programs, and settings to the way they were at a restore point. It does not delete personal files like documents and photos. Programs installed after that point may need to be reinstalled.

Wrong choices

• System Restore reinstalls Windows from scratch: System Restore only returns system settings to an earlier point. It does not reinstall Windows.
• System Restore only restores email: System Restore works on system files and settings, not email.
• System Restore deletes all files created after the restore point: Personal files such as documents and photos are not removed. Only system changes are undone.

Each user has a separate profile that holds their settings and desktop. If only one user has problems, that profile is likely damaged. The technician backs up the user's files, creates a fresh profile, and copies the files back.

Wrong choices

• Replace the hard drive: A failing drive would affect all users, not just one.
• Update the firmware (BIOS/UEFI): Firmware affects the whole PC, not one user's account.
• Reinstall Windows: Other users work fine, so Windows itself is healthy. A reinstall is far more than needed.

A blue screen right after a driver change points to that driver. Safe Mode loads only basic drivers, so Windows can start. From there the technician rolls back or uninstalls the new driver, then restarts normally.

Wrong choices

• Replace the motherboard: The blue screens began right after the driver install. The hardware is not the first suspect.
• Run ipconfig /renew: ipconfig only renews network settings. It cannot fix a driver crashing Windows.
• Defragment the hard drive: Defragmenting does not fix a faulty driver.

Ads in odd places, much higher data use, and apps the user did not install are common signs of mobile malware. The technician should remove unknown apps, check app permissions, update the phone, and run a trusted security scan.

Wrong choices

• The screen brightness is too high: Brightness affects battery life, not data use or ads.
• The cell signal is weak: A weak signal causes dropped calls and slow data, not unknown apps and ads.
• The battery is getting old: An old battery causes short battery life, not ads and unknown apps.