AdFly itself's not a virus, However if you click on the ads and fake download buttons the ads produce, that can get you a virus or an attack on your Windows Host file. Install Malwarebytes Anti-Malware, it's a good piece of software, and unlike many anti-virus software, it's not a system resource hog when scanning files(like norton, avast, and others) which can really slow down your computer, such as when you load wow and things are loaded out of MPQ's so it can load ingame, some of those anti-virus software will scan every single fucking file the game has to load and when it's reloaded, it's rescanned, shit can take forever to load then.