Windows 7 games stop responding ONLY in 7

[bontakun]

i've tried 7 32bit 64bit.. and all the games that i play.. counter-strike:source, left4dead, cod:modern warfare, and now modern warfare2... all games crash after about 5-10minutes of play..

this is the log i've been getting after modern warfare2 crash
Problem signature:
Problem Event Name: APPCRASH
Application Name: iw4sp.exe
Application Version: 0.0.0.0
Application Timestamp: 4af4bdcc
Fault Module Name: nvd3dum.dll
Fault Module Version: 8.17.11.9539
Fault Module Timestamp: 4ae7df89
Exception Code: c0000005
Exception Offset: 00360b46
OS Version: 6.1.7600.2.0.0.256.1
Locale ID: 1033
Additional Information 1: 0a9e
Additional Information 2: 0a9e372d3b4ad19135b953a78882e789
Additional Information 3: 0a9e
Additional Information 4: 0a9e372d3b4ad19135b953a78882e789

i've updated my gfx driver to latest demo versions, updated my sound drivers(im not even using a sound card just onboard)

any help would be very appreciated.....