OK here's the problem: My shuttle sn45g was running fine with 256MB pc3500 and a barton 2500, then i wanted an upgrade, so i bought another identical stick. However I now just get the computer restarting after the windows xp loading screen (with the blue bars moving across before the welcome screen), i.e. not loading the windows desktop. I took the stick out, and it worked fine. So I tried it with some other RAM, and whenever I have two sticks in (of any RAM), it stops working. At the moment I have a spare 512MB stick so i've been using that, but if i want to upgrade to 1GB of RAM then i need to be able to use two sticks. Anyone know what could be causing this or should i just go and take it to the aria shop where i got it from? (they might not give me a refund or replace it though cause i overclocked the proc).