miag : A virus is built for damaging your ystem and will do so for sure...if you donwload a virus, it will surely damamge your system no matter what you do...the only way to prevent that is "REMOVE THE VIRUS".

Norton will surely detect a backdoor creation utility as a trojan bacuse its the job of norton...it identifies most of them!!!

Your laboratory will fail....its really not safe. For doing what you want to look at, you will probabaly have to install the windows on Linux on QEMU or use those viruses upon emulation engine like Wine!!