i don't understand the thread.? ;-(

you want to run AV off of a USB drive - right?

You need the OS.

What I sometimes do is use a live cd linux distro - "Knoppix" - boot from it and scan the local drives - be it windows or *nix volumes.

How effective and the *quality* of anti-virus removal that this procedure provides compared to running an AV scan/disinfect from a reputable vendor (lets say symantec or mcafee) which require the boot of the windows OS ---> that remains to be seen. and can be debated.

as we all know - your anti-virus protection is only as good as the *quality* and update version of the virus signatures and/or scan engine. as many studies have shown recently, there also seems to be a wide range gap in the *quality* of virus removal/protection by the different anti-virus vendors. meaning, not all anti-virus software is created equal and just because you are paying for it - does not seem to *guarantee* that it will protect your machines.

IMHO, the linux/knopp combination is an experimental procedure and should not be used in a real production environment where real users exist and the possibility of a virus infection can cause real down time and possibly cause you to loose your real JOB! stick to the reputable vendors. if nothing else, at least you can shift the blame onto them for not being able to provide you the protection you paid for.