CPU overload

I'm fairly new to computers and all out of ideas. Please help if you can.

The main problem I'm having is the CPU usage hits 100+% when I run various programs such as online gaming, some virus and spyware scans, video streaming etc. It soon overheats and shuts down abruptly. I suspect it's infected but now I can't even run certain programs (like Spybot and McAfee) to maybe track down the culprit(s)

I have a 4 year old laptop. I've never had this problem until 3 months ago, when I replaced the hard drive for the 3rd time. Everything worked fine for a few weeks then suddenly I had problems. The system got slower and slower. It takes forever to start up or open my folders. Then the screen went black for no reason. I've had problems with that before and it turned out to be related to a defective keyboard, so I disconnected it and plugged in a desktop keyboard. The screen works fine now but the CPU usage and general sluggishness problems remain.

The last full scans I managed to run revealed nothing more than a few tracking cookies. (Spybot S&D, McAfee, Ad-aware, etc) McAfee became too much of a CPU hog too handle, so I uninstalled it and tried AVG (free version) I was able to run a full scan, but again, no serious threats detected. My registry is probably a big mess, due to my own carelessness. I've tried removing some programs... also rolling the system back and defragging but nothing helps and now I'm completely lost.

Task manager usually doesn't show many processes running (if I'm reading it correctly) Highest in usage, are: System idle process, Firefox, System, and Tea timer. The only others I currently see running are: explorer, taskmgr, svchost, lsass, iPodservice and BCMWLTRY.exe, which all show low usage (02-04 %)

My crummy machine:
Acer TravelMate 4652LMi laptop
Seagate Momentus 2.5 80 GB HDD
Windows XP Pro (SP3)
Intel Pentium M 740 (2MB L2 cache, 1.73 GHz)
Intel GMA 900

Please tell me what additional info you need from me and what next to try. I can't afford another computer and I'd hate to reformat or replace the drive again and start back from scratch, only to discover it didn't fix a thing! Thank you

 

Your heats problem may be as simple as a dirty heat sink or a faulty fan. Get yourself a tin of compressed air. Unplug the power and blow out all the dust. Then switch on and check that all the fans are turning normally.

 

Thanks but I don't see any easy way to access the fans. It looks like the entire bottom of the casing needs to be removed, and 2 of the screw heads are stripped. Grrrrr. Should I try to blow the dust out through the vent? Anyway, that might help cool it down but wouldn't the underlying problem remain? It seems to me there is no reason the CPU should be working so hard to do so little, unless it's dying or my system is infected.

 

Try what Chairjm said. And yes, you can blow the dirt out of the vents, just use some caution. Most laptops will underclock themselves when the temps get high. Thermal Throtling or something like that...:-D Could be slowing you down.

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