How to restore my windows 8 OS ?

Hi guys,

I have ASUS Vivobook S551LB. The first time I purchased it, it was installed and configured well by Windows 8.
But, I had it formatted and cleared all partitions in it in order to install Windows 7 and Ubuntu.
Since all the drivers are unavailable in Windows 7, I decided to reinstall my Windows 8.
I read all forums say that I could only install it if I have the backups.
Is there anyway for me to restore my windows 8?

How to download and clean install Windows 8.1 if you have an OEM computer with UEFI firmware (BIOS) embedded Windows 8/8.1 product key. -> link

Hi genet, thanks for your solution.
I have downloaded the media installation creation tool, and everything worked fine.
But my problem hasnt been solved since I don't have the product key. Now I am just trying to contact my manufacturer to ask where they stored the information, since I couldn't find it anywhere.
Thanks for your reply btw, It's really helpful.

vadz said:

But my problem hasnt been solved since I don't have the product key.

Click to expand...

How to download and clean install Windows 8.1 if you have an OEM computer with UEFI firmware (BIOS) embedded Windows 8/8.1 product key. -> link

Note: If you have an OEM computer with UEFI firmware (BIOS) embedded Windows 8/8.1 product key, the Windows 8.1 installer should automatically detect product key from UEFI firmware (BIOS).

Note: If you get prompted to enter a product key, it means that you have the wrong installation media and that's when the Windows 8.1 installer can't detect Windows 8/8.1 product key from UEFI firmware (BIOS).

Click to expand...

edit:

Note: After the installation is completed, Windows 8.1 will be activated automatically, if the internet connection is up and running (see screenshot below).

Click to expand...