I purchased a replacement hard drive for a Samsung SIR-S4120 DirecTV/Tivo unit.

I'm fairly certain I did everything correctly during installation (Lou's directions are perfectly clear).

But when I powered the unit up it stalled out at the logo screen (the one right after "Powering up ...") and went nowhere. The same thing happens every time I shut the unit down and restart it; the unit goes to the logo screen and then gets nowhere.

The hard drive is able to spin up -- I've heard it.

What are my next options -- short of getting a non-Tivo DVR from DirecTV?

Is there some way to re-set the unit and try again?

Can I test the replacement drive by connecting it to my home computer?

Is there anything I can try?

Thanks for the help.