My PC is somehow infected with Trojan Horse PSG.Generic3.YSB. Affected file is c:\windows\system32\dllms.dll . Only AVG antivirus finds it. Spybot and/or ad-aware are unable to detect the trojanhorse. AVG (free version) antivirus heels the same; the infection keeps coming back. Object details under AVG says: Healable - No! The source is backup copy. I understand, after googling, that it is a dangerous malware which steals vital info from the PC.
Please help me solve the problem and get rid of the trojan.