My computer is about six months old. I usually keep it running almost all the time. However, if I cut it off and it sits through the night (and the place is not cold or anything, just not hot) when I start it up in the morning, there is a 50% chance it will freeze while loading Windows XP. But if I push the button and cut it off, restarting after about 30 seconds, it never fails to come back on, and everything is great.

Why would a relatively new computer be doing that?