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#21
It would help if you'd explain more fully why you want to repair Win7 in D.
Can you boot into both Win7 using the Dual Boot menu? But D only boots into Startup Repair, correct?
To attempt to repair Win7 on D, boot the Reinstallation DVD, select Repair console on Second screen, accept any offered Repair, if none is offered select the D install to repair.
If Win7 on D won't start at reboot then boot back in and follow these steps to run SFC -SCANNOW Run in Command Prompt at Boot to see if you can repair the damaged or missing System File. You may need to run it several times.
Your boot files are currently on C, but we can help you move them back and then delete C, resize D into that space if that is what you decide. Hopefully Win7 on D will reclaim C letter once the new install is deleted.