If the MBR of a hard drive gets corrupt, it will cause a failure to boot until it's fixed. A possible error message will be BOOTMGR is missing. Fortunately, it's fairly easy to fix.
1.) Insert the Windows 7 DVD into the drive and press any key to boot from it.
2.) At the Language Selection screen, click Next
3.) At the bottom of the screen, select "Repair your computer"
4.) In the dialog, choose the correct operating system and select Next
5.) Choose Startup Repair
6.) Select the Command Prompt and input the following:
Press ENTER after each command and let it finish before inputting the next command.
7.) Type exit and reboot the computer.
If the above doesn't fix the issue, you'll need to fix the boot sector code by doing the following:
1.) Determine the drive letter of your Windows installation CD/DVD by typing these commands in the Command Prompt:
2.) Look for the "Type" column, look for the word "CD-ROM". This item is your CD/DVD installation drive letter. If the letter is D:\, input the following:
If the drive letter is different than D:\, replace the second command with the drive letter you have noted from the previous list volume command.
3.) Type the following command to issue the repair:
4.) After the command finishes, remove the DVD and type exit and reboot the computer.
1.) Insert the Windows 7 DVD into the drive and press any key to boot from it.
2.) At the Language Selection screen, click Next
3.) At the bottom of the screen, select "Repair your computer"
4.) In the dialog, choose the correct operating system and select Next
5.) Choose Startup Repair
6.) Select the Command Prompt and input the following:
Code:
bootrec /fixmbr
bootrec /fixboot
bootrec /rebuildbcd
Press ENTER after each command and let it finish before inputting the next command.
7.) Type exit and reboot the computer.
If the above doesn't fix the issue, you'll need to fix the boot sector code by doing the following:
1.) Determine the drive letter of your Windows installation CD/DVD by typing these commands in the Command Prompt:
Code:
diskpart
select disk 0
list volume
2.) Look for the "Type" column, look for the word "CD-ROM". This item is your CD/DVD installation drive letter. If the letter is D:\, input the following:
Code:
exit
D:
cd boot
dir
If the drive letter is different than D:\, replace the second command with the drive letter you have noted from the previous list volume command.
3.) Type the following command to issue the repair:
Code:
bootsect /nt60 SYS /mbr
4.) After the command finishes, remove the DVD and type exit and reboot the computer.