My tip is to have two PCs.
One "clean" for music production only, running XP. This machine should never be online and all files progs etc should be scanned before transferring. Transfer clean files using a third party stick or hard drive. Latency and slow speed is kept to a minimum.
The other PC for general use can run 7 or even Vista with the usual necessary protection. Backup files and prog files often onto an external device. It is easy to clean out this "dirty" PC at any time. Reinstall O/S if Trojans or other malicious ware is present in the knowledge that all your backed up stuff can then be reinstalled easily. There are progs that specialise in automaticall backing up all files and programs.
PC prices are very cheap right now and 5-600 or so buys two decent spec systems. Why take a chance on a one for all that will not really do everything and uses outdated O/S?