I'm having some odd behavior with my laptop shutting down. Sorry for the length of this post, but I don't know if this is an issue with malware, windows or other software, or a hardware problem. I've had some issues with Windows Update, the laptop shuts down during some hardware diagnostic tests, and also shuts down during some malware scans.
It may be that my CPU is overheating and the BIOS is forcing the power to shut down. However, some malware scans can run for hours with my CPU pegged and still finish. Others can run for hours, but the laptop shuts down before the scan completes, and one scan in particular shuts down the laptop as soon as it starts.
All of the temperature monitoring utilities I've found don't support my CPU (Celeron M), so I've no way to know how hot it's running. I've blown out the fan with compressed air.
If it is overheating, the only way to fix it involves taking my laptop apart and applying new thermal paste. I've never done either before, and not looking forward to it. So I'm hoping to rule out malware or other software conflicts first before attempting that.
So anyway, this is what's been happening:
Often when I boot my laptop, the CPU usage is at 100% for 15-20 minutes, with no applications running. Windows Resource Monitor shows svchost.exe taking 60-70% or more of my CPU. I have to wait until it calms down before I can do anything, and this problem is occurring more frequently.
The first problem I had was windows update not rebooting the system properly. After the updates installed, it would exit windows and show the status of the update like it normally would. After it attempted to boot back up, the screen would just stay black forever and I'd have to pull the power cable to shut down the computer, and then boot back up. Windows shows the updates as installed successfully.
Running windows disk check shows no errors, there's plenty of free space on the drive, and Vista says the drive doesn't need to be defragmented. I ran the built in Toshiba Diagnostic utility, and it showed no errors.
I attempted to run Windows Memory Diagnostic twice, and the laptop shut down (powered off completely) in the middle of the test both times. The same thing happened when trying to run Memtest 86. I've tried one stick at a time, and also tried using the stick that came with the laptop originally (which is most likely good and hasn't been used in years).
The laptop also powers down when I run some (but not all) on demand malware scanners. Using DrWeb CureIt, I'm able to run an express scan to completion. This takes several hours, the CPU is maxed out, but it does finish. However, if I try to run a full scan, it will go for hours, but then power down toward the end of the scan.
I have a folder on my desktop with downloaded application installers for another PC I'm rebuilding. If I attempt to scan that folder with DrWeb, I immediately get a BSOD and my laptop shuts down every single time before the scan can even begin. This happened again today, and after powering the laptop back on, it booted windows repair. The repair was unsuccessful and showed some errors I didn't understand. Then it powered off. Upon powering back up, windows loaded just fine.
I'm able to scan the desktop folder with Panda Online Scanner, and also able to run an express scan to completion. However, I've tried to run a complete scan a couple times, and the laptop always shuts down toward the end of the scan.
I ran ESET's full scan online last night. It ran to completion and no threats found. I was also able to run a full scan with MBAM, and no threats found.
I can't point to any particular event that started this behavior, but the problem is getting worse. Other than installing sandboxie and running windows update, I haven't really made any significant software changes in the last few months.
Toshiba Satellite A135
Intel Celeron M firstname.lastname@example.org GHz
2 GB RAM
Vista Home Basic 32 bit, SP2