newly repaired laptop no longer recognizes ext HD

Hi there --

I recently sent my HP Pavillion dv9000 laptop in to HP after the motherboard and hard drive died. There had been a recall from HP on this very issue, so they repaired/replaced the motherboard and reimaged the hard drive at no charge to me. However, I have a Western Digital external hard drive that most of my stuff was backed up to (I did lose some stuff on my internal hard drive when it died). But my issue now is that after getting the laptop back yesterday and starting to reinstall things and set it back up to the way I like it, the computer no longer recognizes the ext. HD. I'm using Windows Vista Home Edition.

I have three USB cords connected: 1 - my Espon printer, 2 - my wireless mouse hub and 3 - my external HD. It recognizes the printer and mouse USB cords. Curiously, after using the CD/DVD drive to insert my printer's software disc to reinstall the printer, the CD/DVD drive disappeared as well. I called HP and they had me do a system recovery which did bring the CD/DVD drive back (drive E:/) but still will not see the ext HD.

I left the HD unplugged during the system recovery and before I plugged it back in, My Computer did show a "removable disk" in the F: drive (which is the drive my ext HD used to show up as), but when I plugged the HD back in, nothing changed. No plug-and-play, no searching for new hardware, nothing. And the current disk it shows as F: asks me to "insert a disc" when I click on it. Also, a window popped up from the system tray that gave me some sort of "unrecognized USB" message. The only thing the message advised that I do is to reconnect the USB to see if Windows would pick it up (which I've done several times, to no avail).

Of course, HP won't help me now and I'm at my wits end since all of my info., Itunes music, programs/applications are saved on that HD. Can anyone suggest anything? Sorry for the lengthy post, I just wanted to explain it all as thoroughly as I could.

Thanks!
Sarah