Enabling Hidden files And folders By using Registry editor

If your system is unable to view your hidden files and folders, even if you try to change the folder option to view hidden files, you system is affected by some malware or Trojans. To re enable the option to view hidden files, do as given below
Go to START Menu and click on Run
Type RegEdit and press Enter to run registry editor.
Navigate to the following registry key:
HKEY_LOCAL_MACHINE/SOFTWARE/Microsoft/windows/CurrentVersion/Explorer/Advanced/Folder/Hidden/SHOWALL
In the right side verify that the CheckedValue, value data is REG_DWORD type. If it’s not( such as belongs to REG_SZ), then delete the CheckedValue value data. If the CheckedValue has been delete, create a new DWORD(32 BIT)value and name it as CheckedValue.
Double click on CheckedValue and change its value data to 1(virus may change it to 0 or2)
Within the same registry key, verify that the Typevalue data is of REG_SZ type, and has the value data “radio”. If not set it to radio. Virus may change it to blank
Set the system to Show all hidden files and folders, and then check if hidden files are shown or not.

Some viruses may disable the registry editor. Here is the way to enable it.
Start/run
Enter GPEdit.msc and press Enter
Navigate to the following location: User Configuration /Administrative Templates /System/
In the settings panel, locate the Prevent access to registry editing tools option, and then double click o it to open the settings dialog. Select Disabled or Not Configured.
Click on ok button. Try to run regedit.exe, and if required restart the computer.