About 2 weeks ago, hubby opened the case & changed the master & slave on the burners. Since then the computer will start booting up & will shut down before everything has finished loading up. It always gets to where we can see XP logos, often the entire desktop. Sometimes it takes another 1 or 2 times, but it will completely load & will not shut off after this point unless you intentionally shut it down. He reopened the case & there are no loose connections, which was my first thought. The hard drive is older, so I'm wondering if it could just be time to replace the drive---or if it might be something else. We built the desktop within the last 6 months (I think), so the case, power supply, motherboard & processor were new at that time. Just thought I would try to get some input before we try anything.