PE 9 causes crashes after deleting freespace

I had a free version of PE 7 from a computer magasine and it worked fine
except when it got to the point of deleting the free space on the harddisk,
it crashed and needed to be physically reset.
So I bought the version 9, it did the same (even when I tried several
alternative methods of deleting, overwriting). After I'd tried several
times to run the system cleanup option with no success it started to crash
with just when I started PE. So I uninstalled it. the computer then crashed
yet again, and when I restarted XP would not boot. So I put the Ultimate
Windows Boot CD (UBCD4Win) in the drive and from the (I don't know the
correct word in English, its a command line interface to resolve boot
problems), anyway it has CHKDSK, and ran CHKDSK C: /R.
I rebooted and everything has been fine since (without PE).
Is it possible that PE has problems with a SATA disk? Does anyone else
have a similiar problem with a SATA disk?
I'm not going to reinstall PE till I know the problem has been fixed.