If "regedit" is not working you can use any third party software like my favorite is "Registry System Wizard", its a freeware and will give you access to registry.Once you have opened the Registy, just follow the procedure:
1.go to
Key: [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Applets\Regedit]
2.then delete the values: "FindFlags", "LastKey" and "View"
3.restart the windows.

There are many other ways to repair the regedit. Tell me if this doesn't work. I have another option too to help you out.