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CompTIA A+ Core 2 (220-1202) · chapter 12 of 17

Ticket queue: Windows won't behave

In this chapter Objectives 3.1, 3.4

  1. Windows symptoms, part 1
  2. Windows symptoms, part 2
  3. PC security symptoms
  4. Practice questions
  5. Chapter recap

Objective 3.1

Windows symptoms, part 1

Blue screen of death (BSOD)

A BSOD (stop error) means Windows hit a fatal error and stopped to protect data. Note the stop code (e.g. VIDEO_TDR_FAILURE). Usual causes: a new or bad driver, failing RAM, overheating, disk errors. Fixes: boot Safe Mode, roll back or update the driver in Device Manager, run Windows Memory Diagnostic, use System Restore, check the minidump and Event Viewer.

Exam tip BSOD right after a driver update = roll back the driver. BSODs at random under load = check RAM and temperature.

Degraded performance and low memory

Degraded performance: check Task Manager and Resource Monitor for the busy resource, trim startup apps, free disk space, scan for malware, install updates. HDD at 100% all day = consider an SSD. Low memory warnings: too many apps or one app leaking memory. Close the hog, check the paging file (virtual memory) size, and add RAM if it's always short.

Exam tip A process whose memory grows all day and never shrinks = memory leak. Update or restart the app.

Boot issues and No OS found

Boot issues range from slow boots to boot loops. Use Startup Repair in WinRE, Safe Mode or System Restore. No OS found (or 'Operating system not found'): check boot order first (a USB stick or disc left in), then whether the drive is detected in UEFI, then repair boot records.

WinRE > Troubleshoot > Command Prompt
X:\> bootrec /fixmbr
  (rewrite the MBR boot code)
X:\> bootrec /fixboot
  (write a new boot sector)
X:\> bootrec /rebuildbcd
  (rebuild the boot configuration
   data; finds Windows installs)

Exam tip Drive missing from UEFI = hardware (cable, dead drive). Drive present but 'No OS' = boot order or boot records.

Frequent shutdowns and system instability

Frequent shutdowns with no warning: usually heat (dusty fans, failed fan) or power (failing power supply). Event Viewer logs Kernel-Power, Event ID 41 for an unexpected shutdown. System instability (freezes, random errors): drivers, failing RAM or disk, overheating, corrupted system files. Run sfc /scannow, Windows Memory Diagnostic and chkdsk.

Exam tip Shuts off only under heavy load and the case is hot = cooling. Clean the dust with compressed air.

Check yourself 1An accounting app's memory use in Task Manager climbs all day and never drops, until Windows shows low memory warnings. What is the MOST likely cause?

  1. A failing power supply
  2. A boot record error
  3. A memory leak in the app
  4. Dust clogging the CPU heat sink
Show the answer

Answer: C. A memory leak in the app

A process whose memory grows all day and never shrinks is leaking memory. Update or restart the app; add RAM only if memory is always short.

Objective 3.1

Windows symptoms, part 2

Services not starting and apps crashing

Services not starting: open services.msc; check the startup type, its dependencies (a service it needs) and the logon account's password. Event Viewer System log (Service Control Manager, e.g. Event 7000/7001) names the reason. Applications crashing: the Application log (Event ID 1000, Application Error) names the faulting module. Update, repair or reinstall the app; try compatibility mode for old apps.

Exam tip Service fails with 'logon failure' after a password change = update the password on the service's Log On tab.

USB controller resource warnings

'Not enough USB controller resources' appears when too many devices (or hubs) share one USB controller. Each controller has a limited number of endpoints, and USB 3 controllers run out fastest. Fix: move some devices to ports on a different controller (front vs. back, or a USB 2 port), and remove unneeded hubs.

Exam tip A dock with webcam, headset, mouse, keyboard and drives on one port is the classic trigger.

Slow profile load and time drift

Slow profile load: a large roaming profile copying over the network, a slow link, a corrupted profile or heavy logon scripts. Use folder redirection and trim the profile, or rebuild a corrupted one. Time drift: the clock slowly wanders. A dead CMOS battery loses time when the PC is off. Domain PCs sync with a time server (w32tm /resync forces a sync).

Exam tip Clock more than 5 minutes off on a domain PC = Kerberos sign-in failures. Fix the time first.

Check yourself 2Right after a graphics driver update, an accounting PC shows a BSOD with VIDEO_TDR_FAILURE every few minutes. What should you do first?

  1. Boot Safe Mode and roll back the driver
  2. Reinstall Windows from the USB install media
  3. Replace the RAM with new modules
  4. Run bootrec /rebuildbcd in WinRE
Show the answer

Answer: A. Boot Safe Mode and roll back the driver

The crash started right after the driver change and names the video driver, so roll it back first. It's the least invasive fix that matches the evidence.

Objective 3.4

PC security symptoms

Common symptoms on the PC

Signs a PC may be compromised:

  • Unable to access the network: malware or an attacker changed proxy/DNS settings, or EDR isolated the PC
  • Desktop alerts and unwanted notifications within the OS: scareware or a site allowed to push notifications
  • False alerts regarding antivirus protection: fake 'your PC is infected' pop-ups selling fake antivirus
  • Altered system or personal files: missing or renamed files, or inability to access files (ransomware, encrypted files)
  • OS update failures: malware often blocks Windows Update and security tools

Browser-related symptoms

Browser symptoms often point to a rogue extension, adware or changed settings:

  • Random/frequent pop-ups
  • Certificate warnings on sites that are normally fine (on-path attack or fake root certificate)
  • Redirection: searches or home page go to unexpected sites (browser hijacker, changed DNS or hosts file)
  • Degraded browser performance: slow, high CPU from hidden miners or adware

Exam tip Redirection on every browser = check DNS settings and the hosts file. Only one browser = check its extensions.

Check yourself 3Rosa's searches in her browser jump to a 'prize' site, and a toolbar she didn't install appeared. Other browsers on the PC work fine. What should you check first?

  1. The hosts file in C:\Windows\System32\drivers\etc
  2. The CMOS battery and clock
  3. The browser's installed extensions
  4. The USB controller resources
Show the answer

Answer: C. The browser's installed extensions

One browser affected plus a new toolbar points to a malicious extension (browser hijacker). Remove it and reset that browser.

Practice questions

Answer in your head, then open the answer. Ranger's Help Desk has 444 questions like these for A+ Core 2, with mock exams.

Question 1Right after a user installs a new graphics driver from the manufacturer's site, her Windows 11 desktop shows a blue stop error every few minutes. What should the technician try FIRST?

  1. Run Disk Cleanup to remove temporary files
  2. Roll back the graphics driver in Device Manager
  3. Reset Windows and keep the user's files
  4. Replace the graphics card with a known-good spare card
Show the answer

Answer: B. Roll back the graphics driver in Device Manager

A stop error that starts right after a driver install points to that driver, so rolling it back (from Safe Mode if needed) is the quickest, least invasive fix. Replacing hardware is premature when a software change clearly lines up with the symptom.

Question 2A technician added a second memory module to a desktop last week. Since then the PC shows a blue screen with the stop code MEMORY_MANAGEMENT at random times, even when idle. What should the technician do NEXT?

  1. Test the RAM or remove the new module
  2. Roll back the most recent Windows quality update
  3. Rebuild the Boot Configuration Data with bootrec
  4. Increase the size of the Windows paging file
Show the answer

Answer: A. Test the RAM or remove the new module

MEMORY_MANAGEMENT stop codes usually point to RAM, and the problem began right after a memory change. Testing the RAM or removing the new module confirms the cause.

Question 3A technician enables RAID mode in a desktop's UEFI to prepare for a second drive. On the next boot, Windows shows a blue screen with INACCESSIBLE_BOOT_DEVICE and enters Automatic Repair, which fails. Nothing else was changed. What is the BEST fix?

  1. Run bootrec /fixmbr from the recovery console
  2. Boot into Safe Mode and roll back the chipset driver
  3. Replace the boot drive and restore from backup
  4. Set the SATA controller mode back to AHCI in UEFI
Show the answer

Answer: D. Set the SATA controller mode back to AHCI in UEFI

Windows was installed with the AHCI storage driver loaded at boot, so changing the controller mode leaves it unable to read the boot drive. Putting the mode back restores access; the switch can be done properly later.

Question 4A user reports frequent stop errors. The technician wants to start Windows with only a minimal set of drivers and services to see whether a third-party driver is to blame. Which startup option should the technician choose?

  1. System Image Recovery
  2. Startup Repair
  3. Safe Mode
  4. Disable early launch anti-malware protection
Show the answer

Answer: C. Safe Mode

Safe Mode loads only basic drivers and services. If the stop errors go away there, a third-party driver or service is the likely cause.

Question 5A user says her laptop is fast at her desk but sluggish in meetings. Task Manager shows no unusual processes either way. What is the MOST likely explanation?

  1. Windows Update only runs when it is unplugged
  2. The paging file is disabled when on battery
  3. The battery power mode is throttling performance
  4. The SSD becomes fragmented while the laptop moves
Show the answer

Answer: C. The battery power mode is throttling performance

On battery, Windows power modes and battery saver lower CPU speed and screen brightness to extend runtime. Choosing a balanced or best-performance mode, or plugging in, restores speed.

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