I'v used this one for a while, and it seems to work fairly well. It really helped when I was using net zero for free (before it became another "pay" subscription)........they had a million ads, and it calught just about all of them. It's called spyblocker. It keeps tabs on how man bugs worms etc (for those computer techi guys).
Im no real computer guru, but it seems to work. I don't get all those ads & stuff.