Need help removing Infostealer and other issues with NIS 2009

A few days ago I received the message that Infostealer Trojan has infected my PC and NIS can’t remove it. I tried the recommended removal process by turning of system restore and rescanning, but that didn’t do anything. I installed Spy Sweeper and it found a few trojans and removed them, but I still have the Infostealer Trojan message coming up in NIS. I also still have the Fix Now message for NIS and it’s for my Advanced Protection, when I click Fix Now in status is says Not Fixed. I don’t know what’s wrong with Advanced Protection, sometimes it selects itself to the Off position. I’m also receiving a new message that started after my Spy Sweeper scand and clean it’s: “This application or DLL globalroot\system32\MSIVXxlosbqydltuhtiqroymevtxqbwofaoyc.dll is not a valid Windows image. Please check this against your installation diskette.” What does that mean? I just want to make sure my PC is secure and stable, it’s been a headache of a weekend trying to get this taken care of. What can I do to correct these problems? Thanks for any advice…