Fresh Windows 7 x64 Install - ASRock OC Tuner freezes computer

Installed Windows 7 x64 to a 1TB WD Black Caviar to replace a 640GB drive.

Launching ASRock's OC Tuner causes Windows to freeze completely. Hard lockup. I'm not even trying to overclock, I just want to set a target CPU temperature so my fans will throttle down.

Popping the 640GB drive back in and booting into Windows 7 x64 - works fine. Weird.

What's going on? Same hardware, different HD, fresh OS install and yet OC tuner crashes even though it works just fine on the 640GB drive when I plug it back in.