Norton is probably the problem. Norton products have been known to crash the computer after RegVac performs Registry Pack and Registry Restore. RegVac should detect that Norton exists and not allow Registry Pack.
Registry Pack does produce a backup of the registry which you can restore using Registry Restore, but you have to disable Norton before you do that. By disable, I mean make it so that Norton is not running. That means that you have to remove the command in Startup of msconfig that starts Norton and then restart your computer. Make sure that Norton is not running before you run Registry Restore. You will need to restore the backup that Registry Pack put in the Windows System32 directory or a RegVac subdirectory of it.