Instead of going through your Control Panel, try clicking the icon "My Computer" and see there is a list of choices. Select Add/Remove. Try that. Another way to get there is click Run and in the area you can type enter Add/Remove programs. If you still have a problem, click run, and type in defrag, this is like cleaning out the closet in your computer. Once defrag is complete, try it the normal way again. You might just have a simple glitch. Experience has taught me that if I don't defrag regularly, my comp runs slow and it affects everything.
Good luck!!!