Quote - > Quote - A better solution is not to install those programs that have trouble with UAC into the "Program Files" tree.

In the last, and working, install I selected the'Program files (x86)' instead. I'm glad I did something right in the end.

Actually that won't help, as that's a protected directory just like "Program Files" that Microsoft uses as the default location for 32-bit programs in their 64-bit OSs.