Booting from a bootable usb drive - Missing_Operating_System error

I created that Windows 7 bootable usb with Microsoft Windows 7 USB/DVD Download tool. Everything went smoothly. Then I plugged the usb to my PC Desktop and pressed F8 to open the boot menu. I chose the bootable usb and it came with an error Missing_Operating_System. What's the problem here ?

Is your laptop came with "Windows 8" pre-installed ?. Are you trying to downgrade the machine to 7 ?. What is the exact model number of your laptop ? ( for example HP 15-d009TU ).

Yes, my laptop came with Windows 8 pre-installed (Actually now is Windows 8.1). No, I am not trying to downgrade to Windows 7. My laptop model is HP Pavilion 15 Notebook PC. I am trying to install Windows 7 to my PC (not to my laptop).

I am trying to install Windows 7 to my PC (not to my laptop).

Then please specify the details about your PC . Is it came with 8 and are you trying to downgrade to 7 ?. This is important as installing 7 to a normal PC and one with 8 are different.

Anshad Edavana said:

I am trying to install Windows 7 to my PC (not to my laptop).

Then please specify the details about your PC . Is it came with 8 and are you trying to downgrade to 7 ?. This is important as installing 7 to a normal PC and one with 8 are different.

My PC is ASUS P5GD2-X with Windows XP (now) and my laptop is HP Pavilion 15 Notebook PC with Windows 8.1 . I am trying to upgrade to Windows 7 on my ASUS P5GD2-X PC.

P5GD2-X can run "Windows 7" and i have installed 7 to slighly different models of that MoBo ( same family ). Probably it will be your USB drive which is not prepared properly having issues. "WintoBootic" as recommended by "AddRAM" is a good program to create bootable USB drives. I would also recommend giving it a try. Also make sure that the Windows version you are using is 32 bit as your CPU may not be 64 bit capable.

Does the flash stick appear in the one-time BIOS Boot Menu when you plug it in, under USB, REmovable or HD's - you may need to expand one to see it?

If not then write it again using How To Use UltraISO Software To Create Bootable USB Flash Drive which always works. Be sure to use Format button first.

Then see if it appears, and if not boot into BIOS setup to look for any USB settings which need to be adjusted. Does the stick appear in the BIOS Boot Priority order there?



Look over these other steps for doing a perfect Clean Reinstall - Factory OEM Windows 7 which assure you'll get and keep a perfect install.