Use
Trojan Remover. Yes, such a straight-forward names sounds suspicious, but it actually is probably one of the top virus cleaning programs around.
I had a set of viruses, adware, etc. that disabled all normal anti-virus software. It even stopped lesser known things like HiJack This. Then I finally used Trojan Remover and not only was it able to actually OPEN, but it cleared out all the viruses and such like it was liquid on laminate.
You can use the trial.
Anyway, Milkshape isn't a virus, so if you don't want to take my advise, at least turn off that software when you install Milkshape.