Windows not loading

Archived from groups: microsoft.public.windowsxp.basics (More info?)

When I turn on my PC it gets to the screen saying windows
is loading but doesn't go any further, the hard drive
just stops being accessed after a little time and it
doesn't do anything. It loads in safe mode and I have
done a defrag and virus scan, neither of which helped, I
have also restored to last known good config and also to
a restore point a few days ago but nither has helped.
Anyone have any ideas of what could be wrong or how I
could fix it?!