I would bet it is your hard drive. I had a similar situation back in the day with Windows 95. The hard drive was crap, and to reformat and reinstall Windows 95 on that hard drive was to get another failure a day or two later. Considering how long it used to take to do all that, it wasn't fun.
The errors were exactly what happened when my 40 GB refurb drive (I got it for free, so I guess I get what I pay for) died a couple weeks ago.
Melon