Partitioning into a C: D: and E: drive

I would like to set my computer up to speed up the processes for scanning for viruses. Would it be helpful if I had a c: drive a d: drive and an e: drive? The c: drive would have only windows xp on it. The D: drive would have the programs and the e: drive would have my data. My thought is that since viruses try to migrate to the OS if I have the OS isolated I can scan it more often and more quickly.

I am online a lot every day, sometimes for 24 hours or longer either downloading files, listening to music or chatting.