Sol: Open regedit and goto:
HKEY_CURRENT_USER\Software\Microsoft\Win
In right-side pane, change value of "Hidden" to as following:
1 - To show hidden files
2 - To not show hidden files
If it doesnt work, then scan your computer with an anti-virus software.
Enjoy...
![](http://lh3.ggpht.com/_yxRyglZdYpI/SqNi1iBtTSI/AAAAAAAAADU/2NZGgavvyKQ/signature_1.gif)