I was having a ton of trouble with my Geforce DDR card after I installed it and spent almost two months of dabbling around on it and several windows reinstalls until I located the problem. I had my screen refresh rate set at 85hz because I thought that it flickered a little less than 75hz, just for kicks I changed it back to 75hz and since then I haven't had ANY lockups. Has anyone had the same problem? I can't possibly imagine why in the world that the refresh rate would lock the computer up. If anyone thinks they have a possible explanation I'd love to hear it because I haven't got a clue as to how it could affect anything.