Maybe there is a version activation / conflict on your PC? If it activates based on PC chipset (not physical iLok), I would try uninstalling everything related to Melodyne and doing a clean install.

The sale is tempting, just not sure if I will use melodyne often. The nice thing is that you can re-sell the licence. To folks who might be interested, most versions are 1/2 price at Sweetwater until Dec 30th.