Control Panel opening error message

Hello,
I need help on this annoying problem I'm forced to deal with.
Anyway, a month ago I've downloaded a virus that practically destroyed my PC.
I Have done everything in my power to recover it, but somehow I managed to delete something I probably shouldn't have.
Now it's impossible to open Control Panel without a message popping out:

Windows cannot access the specified device, path, or file. You may not have the appropriate permissions to access the item.
Did anyone have a similar problem?
