My mates on the Net most of the time i think his Pc is old. Everytime he is on the net it seems to be crash quite a lot is it the RAM or the Hard Disk?

Raiders

Which version of windows?
What CPU and RAM does his machine have?
What browser is he using?

Also, what exactly is he doing when it crashes and does it crash everytime he does that. Or does it crash randomly? Does it crash only when browsing or other times too? Did this just start recently (Sasser virus) or has it been doing it for awhile? Does he use virus protection? Does the PC act differently in any other ways? Are his temperatures normal? How old is the computer?

How does it crash?

1) BSOD - blue screen of death
2) Freeze - locks up and you can't do anything
3) Reboot - black screen then computer starts over.
4) Misc - please describe.

I think it crahsh jst freeze. I don't know what he does im getting the PC off him this week al will let u knw when it get it ok.

What OS?
Try emptying Temporary Internet Files first. Try online virus scan at Housecalls (Trend Micro site).
Download Adaware or Spybot, update them and scan the PC for any bad items and delete them.
Then post back.