You may need to run System Recovery Options
from the Wn7 DVD or Repair CD so it doesn't depend on possibly corrupt system files. System Repair Disc - Create
Boot in to try Startup Repair again several times from Disk. If it fails, try System Restore or SFC -SCANNOW Run in Command Prompt at Boot
using the options list Command Line.
You can copy out your files using DVD/CD with this: Copy & Paste - in Windows Recovery Console
If Windows 7 is too corrupted to start, you may need to run Factory Recovery if this is factory OEM, use Recovery Disks if you've made them, or find a Windows 7 installer for your version: Reinstalling Windows 7