When you get the installation disc use the instruction below to access the System Recovery Options. After you have opened the command prompt run the commands CKing123 has suggested.
Attention: In order to boot from the installation disc you may need to change the boot order in the BIOS so that the optical driver is the first device in the boot order, and the HDD/SSD is the second devcice.
1. Place the installation disc in the tray of the CD/DVD drive, close the tray and restart the computer.
2. You will be prompted to press any key to start the installation, do so.
At this point the setup process will load files, this will take several minutes.
3. You will now need to choose the Language, Time and currency format, and Keyboard or input method that you'd like to use.
After this is done click on Next.
4. Click on the Repair your computer link at the bottom-left of the Install Windows window.
This link will begin the Windows 7 System Recovery Options.
5. System Recovery Options will now search your hard drive(s) for any Windows 7 installations. This will take several minutes.
No participation is required on your part at this time, wait till it has finished and the next window opens.
6. Choose the Windows 7 installation that you'd like to perform the Startup Repair on, then click on Next
7. Click on Command Prompt from the list of recovery tools in System Recovery Options.
8. Run the following commands.
bcdedit /export C:\BCD_Backup
attrib bcd -s -h -r
ren c:\boot\bcd bcd.old