I know some time you are not able to get hiden files and folder when you click on Tools - in file menu- in that folder option - show hide files and also when you click on any drives to open it ask to open with other programm. This is very common problem due to some virus. So to solve this you just follow some simple steps ....
1) click on Start -- Run - and write - Regedit.
2) then Click on HKEY-LOCAL-MACHINE.
3) and then Software -- Microsoft -- Windows-- Current version--Explorer--Advanced--Folder---Hidden--SHOWALL.
4) duble click at checkvalue (at right side window) and change its value 0 or 2 to 1
5) now close it and click at Start-- Run-- Write Drive Name (like c:) and click on ok
6) click at Tools at File Menu--- then Folder Options-- then View, click at "Show Hidden files and folders" along with it also click (to uncheck) at its options "Hide extensions for known file types" and at "Hide protected operating system files"
7) and click on ok. Now find the file Autorun.INX or somthing like same name and delete it, Restart the system it will open the drive on duble click again