Your best form of defence is to keep your machine 100% up to date in terms of Windows updates and use the LinkScanner feature of a free AV product such as AVG (this will physically block infected webpages from being loaded by your browser). I had an XP machine that was out by only 8 patches. I got so badly infected it took me 3 solid hours to fix. Tried 3 of the best anti-spyware/malware programs all which found something and deleted it, but they were not clever enough as this piece of malware kept on reinstating itself. Only after a lot of manual deleting did I fix the problem.
System Restore is not what most people think it is and Norton/McAfee products deserve to be burned.
Try the above suggestion of MBAM