Disable syskey on a second HDD

So, I made a virus on a test PC that replaces 'Windows XP startup Password' dialog (syskey) with 'it is now safe to tu off your computer' dialog (both these dialogs are found in winlogon.exe.

Now I need to revert back but didnt back the original file up, though replacing it with one in the dllcache does not work either.

if I cant revert back to the original dialog or disable syskey completley I canot login (that was sort of the point originally)

so I put the problematic computers drive into another computer to disable it from there.

Is there a way to disable syskey on a second HDD, norally that drive would be in another PC but to access the drive I have to have it in this PC.

It is drive E: in my case. Would this be possible or do I just need to wipe it and reinstall windows.