Antispy on A Stick?

Just recently read this (I am s~l~o~w in keeping up with the latest tech sometimes), and it sounds like an EXCELLENT method to handle Malware ...

By putting AntiSpy programs on a flash drive, I can make them portable (scan & clean remote machines), and, in the event my own system becomes inoperable due to malware, I will be able to run this flash drive, scan (and hopefully quarantine or remove) with no problem whatsoever ... is this correct?

Right now my BIOS is set to start (run) the D drive (CD/DVD) #1 ... would I need to change that, please?

And what do people do, simply plug in said flash-drive every week or two to update/keep the protection current?