Sorry I'm late but am at the MVP Global Summit writing this from a seminar.
Below are the steps that work most commonly to recover in your situation however note that GRUB can corrupt Windows 7 beyond repair so if you've completed these without skipping any you might choose to go ahead and rescue your files to reinstall. Those steps are in Troubleshooting Windows 7 Failure to Start
Steps to Recovery from Windows 7/Ubuntu Dual Boot failure:
Boot into Windows 7 DVD System Recovery Options
or Windows 7 System Repair Disk
to Mark Windows 7 or it's 100mb System Reserved Partition (preferred if you have it) Active.
Then run Startup Repair - Run up to 3 Separate Times
until Windows 7 starts and it's boot partition holds the System Active flags.
If this fails when System Reserved partition is marked Active, move the Active flag to Windows 7 partition itself and then try the 3 repairs again.
Be aware that sometimes GRUB can corrupt Windows 7 beyond repair when on the same HD. If problems persist I would delete it completely and then for any future Linux Dual Boots use separate HD's booted only via BIOS, or Dual Boot - Windows 7 and Linux - Windows 7 Forums.
If all else fails it may be necessary to wipe the boot sector of interfering code using Diskpart Clean Command
before Clean Reinstall - Factory OEM Windows 7
which steps are same for retail.