Delete your restore files and turn off pagefile before cleaning the stuff out. Windows supports malware squirelling away backups in both places.
Though I thought VISTA was better than that. You are running VISTA right?
As for how it got in there, shrug. An email, thumb drive, mp3, video, anything can be a carrier these days. Even commercial distro's have been infected, including clean, off the shelf thumb drives have been found with factory installed virii.
I'm amazed I don't get more than I do get. Fingers crossed for jinxing myself.