I Think My PC Hates Me

I am convinced that my PC has a mind of it's own, and that it has decided it hates me. I have built 4 or 5 PCs so far, and this is the first one that seems to bear a grudge for some reason.
First it started to refuse to shutdown, instead choosing to start-up again each time, much like a dog who one returning for a nice long walk, brings the lead to your feet as soon as you sit down.
Then it started to show random memory problems causing it to shut down, maybe to make up for the fact that it refuses to shutdown when asked.
Then it seemed to forget what speed settings the processor should be set to, and either started up with a 1GHz speed (about a third of the actual speed), or say it couldn't detect a processor which is kind of spooky since what was then displaying the message?
Now it has taken to randomly stop during boot looking for a hard drive.

Time to get the credit card out again and preform some open box surgery.
OK now I've typed this, lets see if the stupid thing starts to behave itself!