Insert Win 7 installation DVD and boot from DVD drive. While in some older systems you may have to change boot order through system BIOS, most newer systems allow booting from DVD without changing boot order by simply clicking on any key when prompted to doing so.
Step 2
Choose your default "Language", "Time", and "keyboard Input" on the first window and click next.
Step 3
You're now presented with 3 choices. Click on "Repair Your Computer" to gain access to the System Recovery window. Now choose "Command Prompt" in order to run the desired utility which is called "bootsect.exe". type now on the prompt bootsect /nt60 ALL /mbr to repair all partitions. Eject the DVD, and restart computer. Your computer should now boot Win 7 again.
