Teh virus?

you sure its not the mouse? :)

which anti-virus are you running? make sure its current and hasnt been screwed with by any virus.

try trend micro's online scan...

http://housecall.trendmicro.com/

if it isnt a virus, Id reinstall windows, its the ultimate cure all..

that's about what I'd do, just save some of your shit you'll need to another harddrive or something and start over from there.

88, some possible scenarios which have not been mentioned:

Your computer may be trying to resolve an IP constantly or is getting a renewed IP from the DHCP server constantly if you're on a high speed connection. Try disconnecting network cables/modem.

Boot into Safe Mode (press F8 at Windows boot screen) and see if it freezes there. If it doesn't, it could be a driver issue or a program eating up all of your resources.

If you can get ahold of Norton Systemworks for your PC, run WinDoctor and fix everything.

Not all running processes are shown in the task monitor. You mentioned svchost.exe, so you're either in 2000 or XP. Right-click on your computer and select "Manage...". Actually, I think I posted something similar to this in this thread. See what services your machine is running and how many depend on svchost.exe.

Finally, try Housecall by Trend Micro. Online web scan, might take a while with the freezing and all.

{stupid}Oh yeah, try a different mouse.{/stupid}

Hope those help.