Run Startup Repair repeatedly from the install DVD or Repair CD. Startup Repair - Windows 7 Forums.URL System Repair Disc - Create - Windows 7 Forums.URL
If this fails, make sure Windows 7 partition is marked Active using DISKPART: Partition - Mark as Active - Windows 7 Forums.URL
Then run Startup Repair again up to 3 separate times to repair the MBR.
If this fails, open the Command Line again on DVD/CD to type:
Bootsect.exe /nt60 all /force
Then run Startup Repair repeatedly until it starts.
If this fails, you can copy out your files by running the Windows 7 installer, at "Where do you want to install Windows" screen, click Load Drivers
, browse to your files to copy and paste to external, DVD or Stick. Or use Paragon Rescue Disk to attempt to rescue partition and then files.