I was on the computer and all of a sudden it shut down. I thought I kicked the power cord but didn't. I powered it back up and everything looked normal (expect it went to the screen that gives you the option of starting in Safe Mode or Normal, etc.) but shortly shut down again. I waited a while before booting up again - it powered up and shut down as previously. I timed it, and it took exactly 30 seconds from start up to shut down. I tried a couple more times without success, and gave up for the night. I booted up this morning without a hitch but want to know why this is happening. My wife tells me this happened to her a while back. Does anyone know why this is happening? How do I fix it? Is it a virus? Is it a component problem? Help! (Just in case it helps in the diagnosis: I shut the computer down at the end of each day).