Can't offer any advice on the install issue but I've had good success using Microsoft's Program Install and Uninstall troubleshooter where I've had problems uninstalling programs. Download from the Microsoft Support site at https://support.microsoft.com/en-au/help/17588/fix-problems-that-block-programs-from-being-installed-or-removed
Cheers. Robbie
Thanks, Robbie. Actually Magix suggested that as well. Worked perfectly!