[msat]

Right. Same thing happened to me. What you had working was the 32 bits drivers. And they work partialy. If you remember your device was called "iLok" in device manager. With the 64 bits drivers it's called "USB iLok Driver". I can't remember how I got the 32 bits drivers installed in the first place. maybe they were just the vuilt in microsoft drivers. The 64 bits drivers don't work. Windows will recognize the key when you plug it, install the 64 bits drivers but the key won't authorize anything. PT9 will report ilok key not present or drivers not installed as you're getting.
I can't find any drivers that work. It works fine on 32 bits systems. It's just the 64 bits drivers that are useless. Windows is not making it easier either with it's idiotic paranoia and the "I know better which drivers I want for this device" cr*p.

Latest drivers from ilok aparently have a bug.
Sorry I can't be of more help. I hope somebody will find a solution to this or ilok release something that works.

edit:

AVID has no fault in this except for the fact they've made PT9 on ilok auth only.