Have you run the Microsoft Memory Diagnostic Utility yet?
It will tell you which RAM stick may be bad including which chip on the stick.

Used it many times to find bad RAM over the years: http://technet.microsoft.com/en-us/magazine/2008.09.utilityspotlight.aspx?pr=blog


ASUS M3N72-D
AMD Athlon 64 X2 5600+ Brisbane @ 3GHz
4 Gigs DDR2 PC6400 Dual Ch. Corsair
ASUS GeForce 9800GT 512MB x2 SLI
Win7 64bit or XP Pro x64