I would try Revo Uninstaller.

I had a hell of a time trying to get rid of Amazon Unbox and couldn't do it with the regular Add/Remove, then I found Revo and I got rid of it.

It's a free download:

http://download.cnet.com/Revo-Uninstaller/3000-2096_4-10687648.html?tag=mncol

Let me know if it works!