I Had A Problem Like That When Running.....

I had a pretty bad Freeze problem with my HP Pavilion 8655c which is the Computer I'm on now. This Freeze thing was happening when I was running Windows 98SE on a Computer that once housed Windows XP. Everytime I would try to seen an Email or use Outlook Express to send one my Computer would lock right up and like you I had to hit that power key because nothing would move at all. It wasn't until I got my hands on the Windows XP System Disc to reinstall Windows XP this Freeze thing stopped. So I guess it has something to do with the Operating System. When running Windows 98SE I had a System reading of 533MHz on my Processor like it states on the front of the Computer and 127 MB of Ram. Now with Windows XP I have 535MHz coming from the Processor and 128MB of Ram. I don't know if this Information will help in your case or not. But I know how bad that Freezing can be and anything is worth a try.