scook
They both use Toontrack Solo for standalone play. It is a separate download and install. The zip should be located in the EZD and SD2 download areas. You only need to install one copy it works with both products.
It turns out that I Did have Toontrack Solo installed (icon shows on my desktop), and EZD + Superior are not showing.......not sure why this is? In my earlier 32 bit machine, the install automatically did this.....