Hi
A thought, if the PVR was the type that constantly records to the hard disk, then there is no way I would trust it for further use.
The Tivo's work this way, and you can hear the drive being written to constantly.
If you really want to use it, try something like an ultimate boot CD
One possible link is
http://www.ultimatebootcd.com/
I have used some of the tools from this disk.
http://www.hiren.info/pages/bootcd
Philip.