Mister E Man of I.T.

What software do you use for Anti-Virus?

This is a good question, and has two answers... (it's also linked with anti-malware, but I'll cover that separately)

For a completely free, basic anti-virus solution, I recommend Microsoft Security Essentials

This is useful for everyone who has a PC with a legal copy of Windows XP and upwards (including Vista and Windows 7). It is a basic solution (hence the "Essentials" name) but covers most things fine - it has been receiving good reviews from the IT Media.

Download it here

My second recommendation (if MSE is too basic for you) would be AVG Internet Security, I've been using this for many years in it's free form, but it's paid-for version offers some additional functionality including email scanning etc.

Although it's a paid-for version, it provides a complete peace of mind solution (good option for non-technical family members).

Download a free trial here