Fonts folder not working

Hi Guys,

My problem is I can't install new fonts or delete them. When I open Fonts folder (from Windows Explorer or Control Panel) and try to copy a font file there, just the blue circle spinning beside the cursor for 10 or 20 secs and nothing happens, but the folder window freezes. I can kill the Process from Task Manager only. Same thing happens when i try to delete a font from here. I've deleted the font cache file, but it does not solve the issue.

Fonts folder work in Safe Mode interestingly. Windows 7 64 bit Home Premium.

Any Idea?