ustav, you have a virus in your drive....congratulations!!!
1st of all Open any folder & then click on Tools->Options
On options window click on View Tab & check on "Show Hidden Files & Folders" & uncheck "Hide Protected operating system files (recommended)
Windows may prompt you a warning just click Yes.
Click on Apply->OK and browse the drive that you double clicking.
Search for file named "autorun.inf" & delete it, now virus won't run again.
There are many possible reasons, that autorun.inf could be restored again for better results scan your drvie with well updated antivirus.
Reboot your system it would work fine.