Is there an a free virus scanner and ad aware scanner available that can be put on a USB flash drive and used without having to install on a computer when you want to scan that computer. Eg if a computer has virus and there is concerns the virus scanner is not working properly, I want to plug in the USB drive and run the virus scanner on the USB drive.

Have you tried AVG by Grisoft, there's a free version that works pretty well. I can't honestly remember if it let's you run it from a flash drive - I think so though. But it did have a useful feature where you could download updates without having the program installed then use them on a machine that did.

Hope this helps,

Dazza

You can use ClamWin. Although it is not as good as the real time ones, but it can be put in the USB drive and taken anywhere for scanning.