+1 for DOSBox. But you really need to be more specific as to what games you're talking about. I've managed to get quite a few old titles running by using the built-in Compatibility Mode.
Have you tried the FAQ page? If you can run Vista, I doubt that your cpu is to blame. It had been a very long time since I messed with DOS, but I managed to get Wolfenstein 3D running in Vista a while back. Check out: