1. There are many ways to repair your registry: from System Restore, to your installation disk. There are also many Registry Cleaners on the Internet that will do this specific task for you.
2. Unfortunately, if you do a Google search for a Registry Cleaner, the first pages are filled with Registry Cleaners that toot they are free, but scam you into buying them after a quick scan of your registry.These programs will show you how many errors there are in your registry and will offer to repair the first 3 or 4 errors. That isn't going to help you.

3. There are a few legitimate FREE registry cleaners. One that is definitely for free is the Eusing Free Registry Cleaner.
4. Go to the Eusing website (in resources). Click on the download tab or any of the Mirror sites. Once it downloads, click Run and install the program. Once the program opens it will ask for a registration code for a donation.If you observe carefully, there is a SKIP tab. If you want to donate you can. If you don't want to donate and get this application for FREE, just click SKIP.
5. Click the blue letters 'Scan your registry' and wait until the scan completes. It will show you anywhere from a few to hundreds of errors. Click 'Repair Registry'. That's it!