Hardware problems - game crashing!

[Sgt.Phoenix]

Hi!
I am very frustrated with my latest comp config, since I can't play more than 10 minutes and my pc crashes or freezes.
OK my config is:
MB: EPOX EP-8RDA3
CPU: AMD Athlon XP2800 (Running on 2 Ghz never exceeding 61 deg celsius)
RAM: 512 Mb
Grafix: AGP 8x Gigabyte ATI Radeon 9600 128 Mb (latest drivers)
Internet: DSL 364 kb UL / 64 kb DL, or
ISDN 128 kb UL / 128 kb DL
AA: 2.50
OS: Win XP SP2
I have run every 3D and normal benchmark that I know (incl. 3D Mark), but I cant crash it or find problem. But when I play it always crashes or freezes!
I have even tried putting new grafix card (Saphire ATI Radeon 9600XT 256 Mb) but same happens.
If anyone has some idea what I should do please help!
PS Same thing happens when I run Battlefield 2 !!
Thanx

[gottagrip]

may wish to check the AA Tweakguide link I provided under separate thread - if one checks farther back on the link is a dload for an additional XP tweak for AA gaming.

I just dont' know what else to advise.