PC crashes whilst playing CS

[crouching_tiger]

My PC often crashes whilst im playing CS:Source, the screen either goes black or i am left with the last frame frome the game.
Is this something to do with hardware or software?
I say software because i had to use a friends copy of teh game to install steam as my copy7 had a corrupted file in it, coulld the same thing have happened with the CS files?

As for the hardware i have:

Windows XP Pro (service pack 1)

AMD athlon XP 2200,

768Mb RAM,

NIVIDIA GeForce FX 5200.

I dont think it is a virus as I frequently scan my PC with AVG antivirus.

Does anyone have any ideas that dont include buying a
new PC (im broke )

[IneRtia dRaft]

Wow you can play CS:S with FX 5200? Haha.

Yet I think it's a corrupted gcf files in the source folder. Click here:

http://support.steampowered.com/cgi-...i=&p_topview=1

Verifying the files will check for any corrupted files and will delete them after you restart steam.

Try to run SP2 if you can. -.-

Make sure you plenty of power powering up your hardwares.