crash

I am Running an MSI k9n SLI Platinum mainboard with a AMD X2 4200 Dual Core CPU, Two Albatron GeForce 7600GS Series 256MB/128bit with bridge PCIe, Two 1gig 666hz 1.8v DDR2 memmory sticks – One is a Kingston and the other is Veritech, 250g Western Digital sATA HDD, 500w Omni Power Supply and a LG Dvd Burner. Running Windows XP with Service Pack 2 and updates.

When running all above together the System Crashes on certain games. When I remove the Veritech mem stick it doesn’t seem to crash but games stagger GREATly. ?? Any help would be Muchly apreciated.