Time Machine drive won't mount after power failure.

I have a WD MyBook Studio hooked up via Firewire with my G5 iMac (iSight 2.1 Ghz). After a power outage I can't get it to mount. I've rebooted, I've turned off Time Machine, I've connected and reconnected the cables, unplugged and re-plugged the power source on the drive. It will not mount. It will not show up in disk utility. I've plugged it into the second firewire port on the back of the iMac. Nothing.

I plug into my Macbook via the same exact firewire cable and it mounts right up with all the data intact.

So it seems like it much be the Leopard or Time Machine itself that is causing the problem. Lately, Leopard has been taking forever to boot (3-5 minutes on the grey Apple screen and 5-7 minutes on the blank light blue screen before my login screen apprears).

Any ideas?