The only thing I can think of is that, hopefully, Dell designed the recovery drive against the possibility that the C: drive might be scrambled / formatted / replaced and it should be bootable. Have you tried setting your BIOS to boot from the D: drive ? If you haven't, it might be worth a shot.
To do this you need to catch the computer at the BIOS screen, ie just after you have started it up. Usually, to get to the BIOS commands you press either the 'Delete' key or the F2 key a couple of times while the initial screen is showing. This will take you into the BIOS set-up. Using the Left - Right arrow keys move along to the heading 'Boot' and you should find that the existing sequence is : 1st device - CD/DVD; 2nd device - HDD 1, and it should also list your second 'D:' drive. Using the up / down arrow keys, select the D: drive and use whatever instructions are given in the panel on the right to move this D: drive into second place. Usually you do this with the + and - keys. Once you have this drive as second in the sequence, press the 'Escape' key to exit. You will be presented with some choices, choose the one that says 'Save changes and exit'. The computer will now restart itself, and, hopefully, try to boot from 'D:'.
When - or if - it does, you should come to a screen that says 'Repair'. Choose 'Advanced repair / recovery' and you should then be presented with options which will include re-installing from a recovery partition or drive. Choose 're-install', and it should go and re-install the 'C:' drive to the factory defaults.
If this works as outlined above, you will probably find a lot of unnecessary software has been installed, and you will have all your updates to do for everything from the original build date, plus re-installing all your own software. This is a bucket load of unwanted work, but, if you get this far, you will at least have a working computer !
If it doesn't work, and as I said, my only recent experience of doing this is on a Sony Vaio, then it is probably time to contact Dell and see what they have to say.