Your problem is very clear to me. I thought that you want to avoid reinstallation of XP that's why I suggested that you consider buying another camera. It's not a crazy idea. Many times it can be much cheaper and quicker then OS reinstallation. That's particularly true when you have lots of applications and hardware that you have to install latter. I didn't believe that Unlocker will remove the program but I was willing to give it a chance.
Some people will advise XP repair, a process which I avoid because very often it ends up with more problem then you started with.