P45T-A crashes with 2 mem chips, stable with one

[sleepybp]

I have a P45T-A with E8400, 7800GTX,600W enermax,vista 64 hp sp1, 4GB Gskill ddr2 800 kit (2x2gb 5-5-5-15 @1.9V). If I run windows with both ram chips it crashes randomly sometimes before boot sometimes after windows running for 10 min. If I run with only 1 chip (either one) It runs rock stable for weeks of gaming. Had this setup for about 1 month now and initially thought the crash was due to 4gb in xp pro sp1 32. So I ran with only 2gb for a month tried on both chips no probs. Now I just got vista 64 hp sp1 and its the same thing. Crashes with 2 chips but rock solid with either of the 1 chip. Is this a motherboard issue if both chips run fine indiv? Please help me , what are your thoughts? Thanks,
Brian

 

[VirtualLarry]

Have you run the bootable Memtest86+ CD yet? That will test your RAM thoroughly, you can find out if one of the DIMMs is bad.