Try deleting the upper/lower filters:-
WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.
1. Click Start, and then click Run.
2. In the Open box, type regedit, and then click OK.
3. Locate the following registry subkey:
4. On the File menu, click Export.
5. In the File name box, type savedkey, and then click Save.
6. Click the REG_MULTI_SZ data type UpperFilters, and then click Delete on the Edit menu. When you are prompted to confirm the deletion, click Yes. NOTE: If this data type is missing, continue to the next method.
7. Click the REG_MULTI_SZ data type LowerFilters, and then click Delete on the Edit menu. When you are prompted to confirm the deletion, click Yes.
8. Quit the Registry Editor, and then restart the computer.