Computer Keeps Freezing

[justin]

Please can anybody help
I managed to get a virus the other day with an e-mail from [email protected].
My norton picked it up but said that it had already got into my pc.I followed the steps at the symantic site and norton said the virus was gone.Since then though my computer keeps freezing(the mouse and keyboard wont work)and i have to reset the pc at the switch.
Ive re-scanned the pc and have found nothing are the freezes something else or has the virus corrupted my pc.
I think it is about time i re-formatted the harddrive anyway so would now be a good time to do it.Is there any software i'll need to clean sweep the hardrive or will xp just install itself and deleate everything.
Please help im desperte its freezing more and more.
By the way the computer seems to keep functioning in the background as if its still processing stuff.(eg if i was encoding a movie it would carry on encoding even though i couldnt do anything).

[Z]

close down all the programs running using alt+ctrl+del.
then wait for it to calm down.
then go outside for a while.