I have read all the potential and tried the applicable ones before posting a question.
I have a HP Pavilion laptop. The hard drive failed physically and was replaced. First install was Windows XP-SP2. It was very slow with 100% utilization of CPU, by svchost and/or System process. Not believing that I had a real problem, I formatted out and installed Win2000 which I had run for two years before the hard drive issue.
I ran the sysinternal process explorer an I am seeing more of the problem, but not enough to solve it.
Interrupts DPCs and System are all consuming ~33% varies somewhat but the net result is 100 % utilization, making the machine very slow. I am noticing on my work machine, that the Interrupts are not going much higher that 2%. So I am fairly sure that one of the problems, is whatever is causing the (as high as ) 48% Interrupt count on this machine.
It has been virus scanned with a CA antivirus tool and scanned for adware with ad-aware
As part of the investigation, I needed to upgrade IE 5 to IE 6. I downloaded and installed. When I go Help> About, IE still says that it is IE 5, in the graphic portion of this window, but shows the version as 6.00?? I added this part, in case it sheds any light on this weirdness