Can't change the default install directory...

When I go to advance install and change the install directory to D:\Program Files\Calibre\
it still installs to the default C:\........

This is not where I want to install it as I use an SSD for OS only and don't want to fill it with programs.

It should install where I direct it, however it does not, any ideas?

This is the only program that insists on installing to C:

Windows 7 64bit...

Thanks