If you have administrative access you can try manually browsing to the registry section in question, right click on it and hit "permissions." If you can get into that options menu you should be able to give yourself whatever permissions you need to create keys there. If you can't you will probably have to log in as the genuine administrator in order to create that key. If you're in XP the administrator account is probably "administrator" and by default it only shows up when you start up in safe mode. As for what the administrator password is, its impossible to say. Whoever installed windows would have set that up.