SEE HIDEN FILES IF NOT SEEN........!!!

See Hidden Files If Not Seen
The show hidden files and folders may not work sometimes.If we selected Show hidden files and folders, and then apply the changes, that changes may disappear when we open the Folder Options again.
This happens may be due to some viruses.
-------------------------------------------------------------
You can clean the system using an effective Antivirus, and get back the normal situation.
-------------------------------------------------------------
If you want to show the hidden files before removing this virus, this method may work.

Steps:

1. Open Registry Editor ( Start > Run > regedit )
2. Get to this location:

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced

Now, in the right pane, double click open the entry name Hidden. Change its value to 1 and click OK.

Now close the registry editor, and look whether the hidden files are shown or not.