Hi There
I've worked it out with this (had the problem on a HP PC, C: O/S drive D: HP recovery stuff).
P2V'ed the C: drive, got an P2V error at 96-98% (see above article, the partition parts didn't Work for me), ignored error, mounted Win 7 Pro x64 ISO (must match O/S + 32 or 64 bit on physical PC) and booted on that, used diskpart to make partition active, rebooted to Win 7 ISO again, ran system repair, booted PC, got BSOD (because of the HD Controler), fixed that with the regedit part at the bottom of the above article.
Have to say I didn't check if the 100 Mb system was recreated.
All I can say: This fixed my problem, hope it'll fix Yours too.
Have a nice weekend
Kind Regards
Kim