As Reddo does, I use InoculateIT. What some may not be aware of is that they took over Vet, and the program you download and upgrade for free is in fact Vet. The free download means you don't get get phone tech support (you still get email support) or auotomatic notification of upgrades. A fabulous setup which has never let me down.
I usually upgrade about every 3 weeks, but after the happy.exe caught me between upgrades, I have halved that.
And I NEVER open an exe.file on email attachments, no matter who is sending it to me, without running the av over it first.
RD