I use Eset nod32, counterspy, and spyware doctor. If I have time I will also scan with threatfire or a-squared. You can never be to safe when returning someones HD and being paid for virus removal. I yank the HD and slave it to the tech rig to do scanning. It depends on how much data they have really, but I will always scan with at least nod32, counterspy and spyware doc. I will also install some antirootkit apps on their system when I reboot it before I let it go. After having done countless hours of research on the subject (at least 40 hrs online) and also from experience, this is the #1 combo. In my opinion (and many others) norton, kasperskyand macafee are all just "good" and free antispyware programs are NOT good enough even if you have all of them.