i use norton, and the only prob i had concerning mirc and viruses were the dll called regedit.dll (by DragonZap) that is reported as a trojan - the reason for this is that it can write to the windows regestry database.
maybe mcaffee also detects scripted COM objects that does this, but i don't know exactly, havent used McAffee since dos.
but always remember the 3 most important things when working with computers: Make backups, make backups and make backups.... and maybe also make backups.. !
