First of all, this is usually caused by a virus that messes up your user profile, although it's possible to happen without a virus. So before anything else have your computer checked for viruses while running in safe mode. You can search here or Google for instructions on how to scan for viruses.
To fix the error you'll need to restart your computer in safe mode. Start tapping F8 and you should get to a menu for Windows called Advanced Boot Menu. Choose Safe Mode with Networking (this is also what you'll do when scanning for viruses, by the way).
Once in Safe Mode, follow Microsoft's instructions which can be found here under Method 1 to delete the old profile data. It's a bit of fiddling around but it's not too bad - just make sure to follow the instructions step by step.