My series 2 seemed to have a hard drive problem. (Power-off , power-on: Get "Welcome. Powering up ..." and then nothing.)

I ordered, received, and installed as directed a replacement HD. After reconnecting all cables, etc and applying power, I get nothing. (The four(?) pilot lights do seem to be on.) I tried a power-off, power-on, and I verified all cables, but nothing.

I then un-did the replacement, restoring the original HD. I am now back to a perpetual "Welcome. Powering up ..."

Is the replacement HD bad? Does it need software? What do I do now?

Thanks.