If you have the disc with you, please insert it to your DVD rom and allow your computer to first boot on the windows 7 disc. This will enable you to start the installation process then choose the repair application not the installation. Use the repair command prompt to be able to enter the fix boot command.
You may use the following command line once you're in the repair command prompt.
1. bootsect.exe /nt60 c: or bootsect.exe /nt60 all
2. bootrec /fixboot
If you need to rewrite the master boot record, you may use the bootrec /fixmbr.
More commands are available when you type bootrec into the command prompt.
These commands are helpful on fixing windows failure to boot. I hope you find this useful too.