That sucks. I have the same problem with my B&W g3. In that case it is the HD cont-its a rev. 1. Try PRAM reset, MB reset, remove/replace battery. Make sure the laptop is plugged in to the wall outlet. DId you try putting your old HD back in? It could also be a grounding problem. Check evey step you did. Also what speed is the drive? There is an answer somewhere. I know what a pain it can be, youre not the only one. Hang in there and keep trying.
-Maestro