They might call their program 'RegDelete', yes I ran it then searched the registry and I can see it doesn't delete everything (a Lot!) studio tried to put in there. In addition, it doesn't delete all the many files it created, some of which sit in your Windows hidden temp directory. They could be lurking under Administrator/All users/Default User - it's up to you to find them and XP search doesn't do a good job on hidden system files, even though you ticked the check box! Once you lose the XP install list after an aborted install, you end up with a real mess of registry tracks, files and folders. If you succeed in getting Studio 11 to eventually re-install then OK most of the entries should get updated, but decide to abandon the install and you have a permanent history clogging your PC.
Their wizard needs to combine both the registry and file deletes, which their RegDelete doesn't do.
If a re-install finds entries in the hidden temp folder it crashes with messages like 'dll's not found'. On their website FAQ in another section they tell you where the temp file is and to delete it as well as other folders that can stop a re-install.
Sony Firewire I-link only uses 4 pins. The full firewire PC connector usually has 6 pins because the other 2 are used to carry power to the linked device. Since the 4 pin I-link doesn't carry power the only risk should be from data lines which I'd expect to be buffered. Anyway, I was just suggesting that before you assume you blew up the interface, just remove the Fireware controller first and let XP re-install it at re-boot with the camera connected.
Terfyn, have you actually used Studio 11.1 to author a BD disk, because I asked them when the drivers would be available and they said there was no release date.