What model? The procedure varries a bit based on the different ones they have released.

I unfortunatly lost my PVR drive last night, right when I had hooked it into an external IDE cage for easy transporting to the PC for extraction. I had hooked up the cage, left to go eat, and came home to a really loud and annoyning drive. About 10 mins later the clicking of death came, and I wasn't able to salvage it. The good par though is I had a new drive in the PVR pretty quickly so I could watch TV again.