I've uninstalled the program, deleted the directory, and reinstalled it but the same problem persists.
I am thinking it might be something with my PC (my Windoze XP x64 version has some "quirks" at times) so I am installing registax onto my lappy which has a regular 32 bit XP on it. With 6000 frames per AVI I'd expect it to take a couple of hours per video process though