Cannot remove Utilities 15 to install Utilities 16 - in Windows 7

I get a runtime error when trying to remove using control panel uninstall - suspect it is related to the failure of the disk manager option in 15 to run in Windows 7 on my machine. I have opened two customer support tickets - both promised a call back from a supervisor or specialist - neither ever occurred (that's not a surprise). Any suggestions? I'm reluctant to edit my registry manually for fear of messing up other Norton Products current working.