It looks a bit different in Vista from its XP version. The first thing you have to decide is whether you're happy to accept its recommended Restore Point (usually the most recent one). If not, then click the radio button "Choose a different restore point". Click Next.
You'll then get a choice of all restore points up to five days old. If you want to go farther back, check the box beside "Show restore points older than five days". Click next.
Once you've chosen your preferred restore point, go ahead as usual.
Just be aware that SR can be *very* slow in Vista, so be patient.