Trojan.Zeroaccess.B and Trojan.Gen.2 coupled with web redirects - please help

My wife's laptop recently started redirecting websites and the NIS keeps telling us that it's blocking the Trojan.Zeroaccess.B and Trojan.Gen.2 files.  Each time it tells us that the item is resolved and no further action is required.  However, it keeps happening - typically about every few minutes or so.  Any assistance would be greatly appreciated. 

 

The computer is running Vista Home Premium 64 bit. 

 

Thank you.