Cześć PiotrW,
That is why we have a sticky in the "virus and worms" about what to do when a virus has been found.
A av-program, what kind of av product does not matter, is a dangerous tool to use. Always remember that and have that at the back of your head. All newbies and normal users should know this, that if you follow up a virus alarm without knowing actually what is the matter could ruin your installation, your OS, and your network connection. So in case of a virus alert first establish if other scanners also flag this, if only one product does the chance of a False Positive is gigantic. Then if you have a FP and delete an essential system file you are in for some proverbial head-aches. So first upload the file in question to virustotal, get info from a malware fighter here on the forum, and then you can make a confirmed decision what to do, else you could be playing Russian Roulette. Remember once that people were advised in an e-mail to delete an important win32 file, they lost the ability to restore long document names and they could not use Word or Outlook anymore.
Well the lesson learned here is, you have to experience this once to be twice shy the second time, I can tell you. I would never trust one av-scanner and run several non-resident next to avast to be absolutely certain the infection is real and the malware solution is not destroying my appl. or worse. "Nie smaczny", but that is reality, so next time run DrWebCureIt first or scan the file with ClamAV,
pozdrawiam,
polonus