I'd Say AVG Free 8.0.You can download it You must login or register to view this content.. It is compatible with Vista, and provides great protection, maybe even better than Norton and McAfee
The best way to prevent viruses on a Windows PC is to follow these simple steps:
1. Connect your new PC to the internet.
2. Once your PC is connected, proceed to download and install updates.
3. Restart your computer.
4. Realize that while you were on the internet downloading updates, your computer became infected with a virus.
5. Call Microsoft's tech support.
6. Learn to speak Hindi, even if your call was routed to the US.
7. Reinstall Windows.
8. Proceed to step 1.
9. If you've become wiser and decided to ignore step 8, install Linux.