If you suspect a file, search for it on the websites of the top security software vendors, like Symantec, McAfee or Trendmicro to see whether it is a threat.
If you are still not sure, go to Trendmicro and do a free online virusscan. McAfee will provide similiar free online virusscan soon.
If you deleted one file and it keeps coming back, either it is a worm/virus, or it is a system file and Windows restored it for you automatically.
