Ubuntu boots to grub rescue
Solution 1:
If you've got a Windows 7 Repair disc, just insert that, make sure your BIOS is configured to boot from the DVD/CD drive first, and then boot into your Windows Repair Console to get things fixed up.
This tutorial gives you an overview of how to use the repair tools on your Windows 7 Repair disc to fix the MBR so you can boot Windows 7 again.
Essentially, you're going to boot it into a command prompt on Windows 7 and then run the following commands:
bootrec.exe /FixMbr
Or, try the automatic "Start-up Repair" option to see if that works.