I think everyone here that has replied so far has the right idea... make sure all internal cards and connections are secure. While not exactly the same problem, I had something similar happen when installing and uninstalling video cards. In my instance, I slightly dislodged the IDE cable for the harddrive, thus resulting in a machine that booted up, all fans started, but mine would just sit. Perhaps you have a mobo that is protecting itself by shutting down when you have something that isn't secured. Another thought would be a situation where things are overheating. Perhaps the fan for your heatsink has become dislodged, thus creating the shut down, or one of the other fans power connections have become dislodged. This might cause a situation of overheating, thus the shut down, especially if the fan on your heatsink is the culprit. __________________________________ Do you Yahoo!? Yahoo! Mail Address AutoComplete - You start. We finish. http://promotions.yahoo.com/new_mail The NOSPIN Group is now accepting donations to help defer the costs of providing PCBUILD and our website. Visit http://freepctech.com to donate using PAYPAL