Re: hang

The answer above by ralphmark might well be correct.

In a recent thread http://forums.cnet.com/7723-19681_102-561754/laptop-freezes-randomly/ it seems the random freeze was caused by a bad stick of RAM. So that's a good starting point for your investigations.
You can download a free diagnostic (burn to CD yourself) from http://www.memtest86.com/

Kees