Does anyone know of a free Vista x64 compatible AV program?

The whole process is very simple: you need to download the program from the avast! 4 Home Download page, selecting the appropriate language. Then you need to install it, which is a mostly an automatic process. Initially, if you don't register straight away, you'll install the trial version, which is fully functional for sixty days. During this period, you can register yourself on the avast! 4 Home Free Registration page, and you will receive your license key by E-mail within 24 hours. Insert this key into the avast! 4 Home product, and you will receive the non-restricted version of avast! 4 Home Edition, including access to the update service (the incremental update of the virus database), for one year. After this period you can reregister to obtain a new free license key.

Welcome to the free registration of avast! Home Edition, the ultimate antivirus for home, non-commercial use. Both conditions should be met! For commercial environments, please use another product - avast! Professional Edition.

avast! 4 Home Edition works for 60 days after the installation in demo mode. You will obtain your FREE license key by E-mail after the registration. The license key is valid for 1 year. After one year you will need to just re-register.