Great question — answering as the UphillTech team:
Do you have the Windows 7 DVD? If so, boot from that and select Startup Repair. Once you do that, you will have the Windows 7 boot manager running and can go from there.
Full answer by Dima: https://superuser.stackexchange.com/a/582852 (CC BY-SA 3.0).
Need it done for your business? UphillTech.