|As far as I know, this is an error in the registry of windows.|
The problem is, that you can't correct things in the registy, while windows is not running.
So the easiest way is, to copy your data to another hard drive or DVD or whatever and install windows from scratch.
If you can connect it to another computer, you can manage that in that way, or you can use a Linux LiveCD like Knoppix, which give you also the ability to backup the data of that drive.
The original poster should always write the last response !!!
Let us know, if the problem is solved !!!