New HD, now 100% CPU Usage

[paramount]

Hi,

I was able to put in my new Seagate ST980815a hard disk, but now I'm having a new problem: 100% CPU usage at all times, and the computer runs very slowly. I am not certain this happened immediately after putting in the new HD--I wasn't paying close attention, so it is possible that I picked up a virus or something else coincidentally happened right after I replaced the HD. I thought it was somehow related to the AVG antivirus software I had installed, but I removed the suite and the computer still runs slowly and at 100% CPU usage.

[Harryc]

Look in task manager, which program is consuming the most CPU %?

[basketb]

One reason for the high utilization may be that the new HD is accessed via PIO rather than Ultra-DMA (explorer.exe consuming 100% of the CPU or close to that, would be an indication of this).

[paramount]

I think the problem is resolved, but not explained. First, more background:

I replaced the hard disk, had several problems, but ultimately got things working. Did a brief test (surfing the web via wireless modem in my house as usual). Went on a trip. The 100% CPU problem surfaced during this trip, while I was using a USB mouse that I don't normally use and while connecting via a DSL wireless modem that I don't normally use. After several hours of trying various things, including AVG/spybot scans, removal of the AVG software, etc., I then happened to unplug the mouse. CPU usage went instantly from 100% to <10%. I could re-plug the mouse and not get 100% CPU usage, for some reason. But web surfing was still painfully slow. Other computers using this modem seemed to have reasonable network speed, but not my T23. I just got home and tried the computer using my wireless cable modem at home and it seems normal, no problem.

So essentially my problems were caused by a USB mouse and some sort of wireless network compatability issue.

The main user of CPU during my problems was "system idle process", and when I chose "view kernel" the kernel activities were taking most of the CPU.

[RealBlackStuff]

"system idle process" is just that, it does NOTHING.
If that takes up to 100% CPU time , it means it's idling up to 100%, i.e. doing NOTHING.
Sounds like a wild goose chase.