If you are up to some more tower defense goodness, here is a tower defense game from BitDefender. Defend your system from viruses, trojans, and all that by building variety of towers with different strengths and weaknesses.
You can play the game at http://www.viruswarsgame.com/. I was about to embed it here but it’s 650 pixels wide which is way over my layout limit. Have fun playing!
Some more Virus Wars tower defense game screenshots: