Please try this:
This type issue could be caused by a USB virus. It will spread to all of your USB memory devices and hard disk.
Here is a tool to remove the virus and vaccinate your USB against further viruses.
Download UsbFix (created by El Desaparecido) on your desktop.
If your antivirus gives an alert, ignore it and temporarily deactivate the antivirus.
Plug in your usb devices (Flash drive, pen drive. External HD etc...) don't open them.
Double click sur UsbFix.exe.
Click on deletion
Let the tool work.
Moderator/virus security contributor
At the end of the scan a report will show which you can copy and paste here..
The report is save at the root ( C:\UsbFix.txt ).
You can also vaccinate against any virus.