My Win2k PC (Service Pack 4) has just started having a problem whereby the CPU usage fluctuates for no apparent reason and sometimes goes up to 100%. It becomes unresponsive and unusable, even before it gets to 100%.
This can happen when no applications are running. It is very difficult to tell from Task Manager exactly which process is tying up the CPU (update speed set to low) - it doesn't seem to be any of them! Sometimes, the CPU usage looks as though it is low, but the system is still very very very slow - we're talking a minute or two before it will respond at all and then it does so very slowly. I have run AVG and Trend Micro antivirus (online scanner), which found nothing. Adaware and Spybot find nothing significant. Are some processes hidden? Is there any way of showing everything?
The system seems to be ok in Safe mode.
Rebooting used to fix the problem for a few hours at least, but today (after a power outage) the system keeps getting really slow after a few minutes of use. Sometimes rebooting takes ages - it gets stuck for a few minutes on the "Starting Windows" page.
When in Task Manager, the bottom of the window will say something like CPU 65% and the System Idle process will be 99%. How can that be right?
Is it possible that it's a hardware problem? Could a faulty or overheated CPU cause this issue? Leaving the computer off for a few hours seems to improve matters - but maybe that's just coincidence as it will sometimes run for days without a problem.
I want to avoid having to reformat if at all possible, mainly because I am not convinced that reformatting will solve the problem - unless anyone knows different?
All help gratefully received