yes it does... the power to the drive has no effect on the firewire signal... however there is no power button on the device...so it will stay on unless you turn of the power to the adapter or unplug the power cable... the rest of the time it automatically sleeps depending on inactivity :)
Sorry for the late response. I am almost certain it is a 5400rpm drive. The only reason I say that is because if it was 7200, they would promote it all over the box. 5400 is on the lame end and they would make it a point to leave it out. Ya know?
NOT that I'm an expert in this area (I'm not), but I'm surprised your computer doesn't recognize it. Stupid question, but I'll ask it, anyway. Are you using a PC, or an Apple? It was a couple of months before I hooked up mine, but I think that, at the time that I bought it, it clearly stated that it was for an Apple, only. That stood out in my mind, for some reason. I could be wrong, but I don't think so.
Anyway, I'd definitely get a hold of WD. They are very helpful and I don't think you would have a problem with them. Let me know how you made out.