Hey guys, been a while since I've posted on here...
Basically I bought another 2 gb of ram a few months ago, and they ran completely fine till mid december ish when i brought my rig back from a mates at uni. Then I started getting frequent blue screens of death half way through booting windows. So I did a reinstall and vista wouldnt even finish installing, kept crashing after the required restart. Had the same problem when I tried XP. So took all but one stick of ram out, and it worked fine. Instantly. Sent 2 of the sticks back to OcUK, they sent new ones back, evidently the 2 new ones were faulty after all. I still get the blue screens though, even with the new ram. The strange thing is though, they only happen when I have all 4 sticks in together. Its completely fine with any combination just 3 sticks, but as soon as I put the 4th in it blue screens. Ive tried using a different motherboard, get the same error. Ive also tried a different cpu, and same problem again. So I'm currently running on just 3 gb (which I know is plenty, but it would be nice to be able to use what I paid for), and have no idea what to try. Any ideas?

Thanks guys

(and a late happy xmas and new year to all ^_^)