This article explains how to repair Windows 7 with the Startup Repair Tool after booting from the Windows 7 DVD. If you do not have a physical DVD, you can create a Windows 7 System Repair Disc.
The Startup Repair tool repairs Windows 7 by replacing critical operating system files that may be damaged or missing. Startup Repair is a simple diagnostic and repair tool to use when Windows 7 won't boot properly and you can't enter Safe Mode.
To start the Windows 7 Startup Repair process, you must boot from the Windows 7 DVD.
There is no user intervention required here. Simply wait for the Windows 7 installation process to load files in preparation for whatever task you wish to complete.