ping for later
I've had very good luck with hijackthis, AdAware, Spybot Search and Destroy, and F-Prot. Sometimes, I even have to trick the spyware by making it think the system is already infected. However, some of my customers require a complete re-install of the OS. On some occasions, the same customer comes back 3 days later with an even worse spyware infection, even though his system had been completely wiped and reloaded. Lately, I've been creating image backups of systems with a program called Acronis True Image. Ultimately, it all comes down to a backup solution of some sort. Saving important files to CD or DVD first, then creating an image of the entire partition containing the OS.
SpywareBlaster. It's free, works better than Spybot, in the background, with no input except updating definitions weekly. It's also FREE.
Do it. NOW.