PKD, you'll find that almost all programs install at least some things on the boot drive, regardless of where you tell them to install. There's just no way to get around it, and you have to make allowances with the size of your drive. I also have a different "Apps" drive (D: ) to install to, but the boot drive (G: in my case) keeps growing with bits and pieces.
Videowave and MyDVD are indeed intertwined and need each other. Well, at least MyDVD needs Videowave. Depending on which services you stopped, and where they were installed, you can try restarting some of them to see if maybe you didn't delete the pieces they need, and you can get Videowave and MyDVD going again. Failing that, you're probably going to have to reinstall and leave Roxio Burn and Back On Track installed. (Though you should be able to stop the services for at least BOT, and I think you can stop the service that notifies Roxio Burn when a new disc is installed.)