Or else, if you want to this this the hard way, you can install windows xp on a usb drive/external HD. and connect it to your pc, and you'll be able to enter in your pc-s C
WINDOWS/System32/ and copy paste the logonui.exe file from the windows that you installed on your HD. Breakfastclub's solution is much easier and faster to do.If you don't have a Windows XP Cd, you will be obliged to take your friend's Hard disk or from the one you wrote this thread, boot windows xp via the HD, copy and paste the logonui.exe file into YOUR computers C
WINDOWS/system32/ directory.That's all. hope i helped you.