One thing that can be done to clean Registry values is to run a Registry cleaner, like CCleaner. I would strongly suggest that you first manually create a System Restore Point, and then take advantage of CCleaner's offer to create a Registry backup, just in case. Run it several times to clean out all vestiges of PrE 1.0.
Also, getting back to the problems with PrE 1.0 and burning, please list the full specs. on your system. It is likely that what caused the burns to fail in the earlier version will still be there, and cause problems with PrE 8 too. Pay special attention to your I/O sub-system, i.e. your HDD's, their size, speed, amount of defragmented free space, controller type and how they are allocated.
PS - are you running as Administrator? You should be.
Also, when you go to install, make sure that all AV, pop-up blocking and spysweeping software is turned OFF, along with all Windows firewalls, etc.
tried your suggestion about CCleaner
ran it several times
but the files are still there in the registry,,,
Have you tried reinstalling it so that you can uninstall it?
Otherwise, I'd just delete the Program Files and ignore what the registry cleaner doesn't get. What remains should be relatively benign.