If your Windows 7 install hangs at the black "starting windows" screen during the first re-boot after installation then you might want to check out the Windows 7 Startup Repair tool.
Check out our Windows 7 Startup Repair FAQ which describes what it does an how it starts automatically to try and fix your problem.
Read more at
- Advanced startup options (including safe mode)
- Resolving stop (blue screen) errors in Windows 7
- System repair and recovery
- What are the system recovery options in Windows 7?