My computer is about 18 months old. Never had a problem before. Starting yesterday, I can no longer start up my computer. It is hung up in a continually loop -- always!. After 2 or 3 seconds of the normal sounds and lights of a start up, you hear a loud "click" and it automatically starts over and trys to start up again -- repeat, repeat, repeat...... All the various lights on my CD Drive, DVD Drive and green & yellow dashboard lights are flashing as well. The only way to make it stop is to turn off the main power. It doesn't even get far enough in the start up routine to try the F8 save mode. It doesn't get that far and restarts. I've never seen anything like it and I consider myself pretty knowledgeable about computers. Any help would be appreciated. Note: my first hint that something was wrong happen at shut down. The same basic thing happened. I would click on "Shut Down" and the computer would start to shut off and then suddenly reboot all by itself (no, I didn't select restart!) The only way to turn it off was to manually power it off. Now, I have the problem mentioned above. More notes: I've loaded XP Service Pack 2. No recent upgrades or software installs. I've tried a bootable floopy and a Rescue CD, but the startup process doesn't get far enough along for it to work.