Everything Ally said!
With the following addendums......
I would tend away from it being hardware if it goes boom at the same point each time, there's usually a random element [1]
this lot.....
http://www.svp.co.uk
Have nice enclosures for about 20 quid, I just got one and they are moron proof....6 screws 2 leads and no drivers.
But scan the crap out of it as soon as you attach it to another machine, and for god's sake tick "do fuck all" if windows pops up a "what should I do with the new disc" box.
Worth trying one thing though, as soon as all the first guff you see vanishes stab F8 like a mad woman (takes a few tries to get the timing right) until it shows you a menu offering "safe mode" and select that.
If it boots in safe mode, we will speak again.
[1] unless you clock your cpu up25% like some tard did yesterday, resulting in the machine not being able to stay awake long enough to get to BIOS
(got it there in the end and set it back to something more reasonable)