How to fix missing operating system?

Question

My operating system is windows 8, I change boot mode from UEFI to Legacy, then after I save the changes it restart and it says "Missing operating system".

Answer 1

Here is what you can try. Boot the Windows 7 or Windows Vista DVD, choose Repair and then Open a Command Prompt window.



Now enter the following commands one after the other and hit Enter after each:



bootrec.exe /fixmbr

bootrec.exe /fixboot

bootrec.exe /rebuildbcd

Reboot your Windows system.



This should hopefully and have made your problem go away !

Answer 2

Fix Missing Operating System error step.....



1) Download EBCD and burn it to CD/DVD according to the instructions, then set up your BIOS to boot from CD. You need full EBCD version to actually write changes to the disk, but it's recommended to try demo version first to make sure there are no hardware incompatibilities.



2) Boot from EBCD, wait until the main menu appears.

Choose "Mount & Boot Center" in the main menu or press F5 and wait while EBCD scans all local disks for Windows installations

Missing Operating System Fix with EBCD - Main Menu



3) Find boot loader for your primary OS in the list. Please note that "called by BIOS" radiobutton is off:

Missing Operating System Fix with EBCD - Bootloader is not called by BIOS



4) Click on the radio button "called by BIOS" for bootloader of your primary OS. It should be turned on now:

Missing Operating System Fix with EBCD - Bootloader is now called by BIOS



5) Click OK to close the window and then choose "Reboot" in the main menu. Missing Operating System problem is fixed now.

Missing Operating System Fix with EBCD - Probem Fixed, Rebooting



Please note: Mount & Boot Center verifies entire boot path from BIOS to the OS boot loader, so other boot problems may be automatically fixed at this point.

Answer 3

1) try to enter into the bios setup by pressing delete button/f2 when you boot your system. in boot option set the first priority to Hard disc.



or



2) insert OS cd. then try to repair the os. ten system will automatically fix whatever problem your os havtable e

Answer 4

Change it back to UEFI in the bios, windows 8(8.1) installs to UEIF by default, as you've changed it to legacy of couse it can't see the files it needs.