Vista - wiped MBR and HEAD of disk - how to recover?

"Okay, I managed to fix this, so I figured I'd post the steps in case someone else gets in a similar situation.

Firstly, I determined the commands I ran overwrote the master boot record as well as the partition table. Nothing else was damaged.

The Windows repair process had written some odd data to the partition table. So I re-ran MBRWiz /Wipe=head and /Wipe=MBR to get back to zero.

After that I ran testdisk again. This time it accurately detected there was no partition at all. I had it run a deep scan and it found all the previous partitions, including the repair partition, XP and Vista.

After recreating the partitions (I did this simply by using the default settings from testdisk for the partitions it found automatically, and simply changed their status from ""D"" (deleted) to ""P"" (primary) or ""*"" (boot)) and seeing my data intact (huge relief!) I needed to make the partition bootable (since although I had marked the partition as bootable, it lacked the proper MBR).

To do this I booted from my Windows DVD. I ran fixmbr and fixboot - which although didn't make the system bootable, did allow the Windows DVD to see the operating system. I then ran the automated Windows Vista boot repair, which made some changes, and I then got a new error message. So, I ran it a second time, and voila, all fixed and I was back in Vista.

The only negative side-effect was I could not boot into XP anymore, but it turns out having the dual boot with XP was what was stopping me from updating Vista to SP2 or Windows 7. I got all my stuff off that partition, removed it, and I'm now running Windows 7 (running an upgrade, which worked flawlessly) with everything completely intact.

Thanks everyone for the help."

You could try reinstalling Vista. If it detects your existing install you should be able to install over the top of it to retain your existing settings.