KingOfChaos

Just about the same system I am running, since it is also an A-Series by HP. I personally love this computer, as I have had very little issues with it since it was purchased (with the exception of the USB legacy being disabled out of the box).

Personally, I would email or call HP about the problem. It could be anything from a bad RAM chip to a faulty processor causing the lock up. Lock ups are pretty much a symptom of just about every type of software and hardware failure, so it's a little hard to trouble shoot without being at your computer.