The drive, according to Disk Management, is "Healthy (System, Boot, Page File, Active, Crash Dump, Primary)". However, I still ran the steps with DiskPart outlined in your guide, which is very helpful.
I ran bootrec /fixmbr and bootrec /fixboot and then Startup Repair (all from Windows 7 DVD). However, none seemed to fix it.

I still can't get into "Repair Your Computer": same error.
Thanks again for your help, much appreciated!
EDIT: Wanted to create a restore point before installing a program and this is what I saw:
Freaky. Yeah. I tried turning it on for "System" but gave some error about an incorrect label. I went to My Computer and renamed the drive from "Windows 7 x64" to just "Windows 7". That turned System Protection on for both drives. I may remove "Windows 7 x64" from that screen.....don't need any of those old backups anyways, as I made an image last night.

Thought this might help? I will rerun bootrec /rebuildbdc /fixmbr /fixboot and Startup Repair.