" The D partition was presumably a partition from which you could restore Vista to C.". Perhaps you're right, ignatzatsonic. I'm semi computer illiterate.
"It looks like you may have installed Windows 7 to what used to be D, thereby overwriting your previously available recovery partition?" Correct.
"And did not touch C, where Vista was originally installed?" I wiped C as well before installing 7.
So what you're saying is that D was nothing more than a recovery partition?
If so, should I just get rid of the D partiton altogether?