The reason why the disk is needed is because it is trying to run Roxio's uninstall program. That should be the best way to uninstall it. I would suggest either finding a friend that has the disk and using it or going to the Support section of the Roxio website and asking them how to uninstall it.
If you don't go that route, you can delete that program's folder in Windows Explorer and run the Software Cleaner in RegVac's Expert Zone to remove entries from the registry. These may not find everything. It all depends on where Roxio puts its files and entries.