Great
The easiest way to fix it, I think, would have been to remove the old disk and boot from a Win7 installation DVD/external drive, and chose to go to command prompt.
Then, simply:
c:
cd boot
attrib bcd -s -h -r
ren c:\boot\bcd bcd.old
bootrec /RebuildBcd
Last line is the only relevant one. Most likely you did not have the bcd file at all - that was the problem.
bootrec /RebuildBCD would have scanned your drive, found the windows installation, asked you a couple of questions, and created the new BCD.
So far, it always worked for me. I even used on a broken RAID set.
No need for external tools. But I've heard a lot of good things about EasyBCD