Got some strange memory error on 2745 build (Vista)

[vorob]

Ok, all was perfect but today i've got this message:
http://picasaweb.google.com/Babudzia/Other#5320441882570513058

I've changed nothing! No new drivers, no new anvitirus, no new software. Yesterday all was ok, and today this crap.

c2d 3000mhz 4gb ram vista 32 radeon 1900xt 9.2 catalist