As a general rule I don't use Ubuntus upgrade option - it's been broken for years. I keep a separate /home, and re-install completely. Works fine, and recognises the userid and uses that to keep all options safe. You could do likewise, even on a broken system from a liveCD to setup your /home if you can find the space.
If you got a grub rescue screen sounds like grub was upgraded to grub2 - may have been all along I guess. Grub2 (on Ubuntu at least
) complains when installed to a partition boot sector record, but appears to work o.k. You could do that from the liveCD, then update the bcd to pick it up. I use EasyBCD and version 2 works fine with Win7 Ultimate 64-bit.
for grub2 recovery on Ubuntu.