I have 4 (1gb) sticks of ram (ddr2-675). My system refused to load to desktop recently ( Ive had the sticks since Febrary). WHen I took all of them out and put my spare ddr2-533 sticks it loaded to my desktop. Also I then took out the ddr2-533 and put one ddr2-675 stick in and it loaded but when I played a game I got the blue screen of death. I shut my system off and took out that stick and put another in. For a few hours I was on the computer again playing a game and I never got the BSOD. Does this mean the other stick was bad? I have the 3rd in now and everything seems ok.