When I google the HD serial (as I said) I immediately see it's Seagate Baracuda 7200. I'd run bootable
Seagate Seatools which can sometimes repair problems, followed by
Disk Check from the installer's Command Line once you get into it.
I thought you had already tried booting the Dell DVD. See if you can boot into
System Recovery Options to run Startup Repair a few times with reboots, System Restore if it's not automated by Startup Repair, Disk check. If these will actually run then it's likely not the HD and you have all the possible fixes to try in
Troubleshooting Windows 7 Failure to Start leading up to file rescue to run
Dell Windows 7 PC Restore or get the superior
Clean Reinstall - Factory OEM Windows 7 with that same Dell DVD.