It seems that your Win is infected by a worm. Could be Conficker, Kido, Downadup mostly trasported by FlashDrives.
You can search for the each specific tool to remove each one or do most recommended: run a complete system scan. And it's best to use at least 3 different antivirus and 3 different anti-malwares.
You could use:
McAfee Avert Stinger
For Conficker you'll have to update Windows to avoid future inffections. Update your system from Microsoft/Windows Update (all critical updates at least).