Ohhhhh. Man, that does suck. What you can't remove with Add or Remove Programs, use something like CCleaner to get rid of the Run keys in the registry. Then you can safely ignore it.
It sucks even more having to make floor model computers usable.
Um, you just should get all of the anti viruses, then take the best parts of each from the source code and make your own anti virus :P. Experienced hackers have made programs that sneak quietly below your AV's activity tolerance and can take the AV out, then do stuff and go away removing all traces anyway.
I highly doubt they would have thier source codes availible to the general public because that is like saying hey hacker we will just make your job easier for you.
Best bet is just to get a free AV if anything and like others have said just use common sense. If you dont use common sense while online no AV is going to be able to protect you.