I've got 4x2GB of crucial Ballistix memory (BL25664AA80A.16FE5) in my machine which is a custom built E6750 on a Gigabyte P35-DQ6. My system drive was a single RAPTOR 150GB but I upgraded to running RAID 0 RAPTORs when I upgraded to Vista 64.
Back in March of 2009, when all of this started happening I was running 32 bit windows XP when one day my machine started randomly blue screening on me. It wasn't an immediate blue screen. First, programs like World of Warcraft would give me memory errors, then if I didn't turn off my computer, let it sit for a few seconds and turn it back on, it would blue screen. Sometimes it would BSOD when nothing was running and I was away. It didn't seem to have a patern. I checked the minidump files I found there were at least a dozen different items causing this to happen. So I decided to update to Windows Vista 64, thinking it might be a software problem (even though I really felt it was hardware). The problem went away for almost a month, then one day it came back.
At that point I decided to downloaded Microsoft's memory checker and every time I crashed like I mentioned above, the system would show my memory as full of errors. If I turn off the machine for a while, and let it sit, the tester shows them as passed without errors. In order to make the problems go away I had to turn my computer off completely and then start it up 10-20 seconds later.
At that point I decided I probably had bad RAM so I borrowed 4 sticks from another computer and put it in. The problems went away for about 2 weeks, then BAM, back to the old error/BSOD routine. I just sort of put up with it...
So in June I moved to a new house... and strangely enough, my computer works just fine for almost a month, then BAM same ol' same ol'.
Eventually I decided to try one more thing which was to replace the UPC...and again my computer worked fine for about 2 weeks and then starts crashing.
I'm thinking either bad PSU or a bad motherboard. I'd swap out the motherboard but Gigabyte doesn't do cross shipping so... I'd either have to be out of my machine for a few weeks or go buy a new motherboard.
PS. I am not overclocking in any way. My RAM is set to exactly what the crucial rep told me to set it to.
If you can get gigabyte to send you a replacement board, do it now before your warranty expires. You might find a cheap open box board at newegg to tide you over. Get another gigabyte and you might avoid a format. You also need to list your system specs, down to the video card and power supply brand and 12v rails on the ps label. Without it, you'd be just guessing and throwing money away. Cheap ps could cause your problem, or too much stuff for your ps ratings.
Don't rule out the PSU. Another member who had lots of memory issues replaced the PSU and that apparently resolved the issue. At a minimum I would disconnect and reconnect the PSU from the motherboard just in case there's a bad contact on one pin.