Hey-
I had computer issues last weekend also related to hard drive not wanting to boot. When you first tried to boot up did the hard drive make any noise (before you smacked it)? Did it sound like it was trying to spin up but just didn't have enough in it? I was dealing with that with my laptop last weekend, was sure that it had bit the dust, and was ready to go out and buy a new one when it randomly decided to boot up again.

Actually, smacking an almost dead hard drive isn't always a bad idea. you might want to try that again, or when you open up the computer pulling out the hard drive and whacking just that. This can help if it is a mechanical problem and the disks are sticking and having a hard time spinning up. If this is the case, the hard drive may boot up again, but plan on backing up everything right away and realize that the hard drive could go at any time.

Since my computer decided to boot again it has been fine, so I am holding off on buying a new one as long as possible (but it is all backed up now!) I think that the computer got scared that I was gong to replace it!

Good luck!