I scan with every free/sharetool AntiVirus, Trojan removal tool i could find..
caution should be taken when running "security tools" Ive found viruses and trojans this way there are sites out there created to just to share thier warez and in my opinion this is the easiest method of planting a trojan into somones network or computer give em a program to play wit plant some software designed to look good with a few custom featurez.

Try to stick to reputable sites and use demos if you have to, but as one of the sigs I saw in this thread BE Paranoid and try not to be reckless.
Personaly I hate being paranoid, and the more I learn the more paranoid I get....its a sickness I tell ya

best form of safe sex is abstanance
best form of a safe networks is ......there is none