Windows 8 Oem Install

I have a lenovo laptop

It came pre installed with windows 8 ( not windows 8.1)
I downloaded windows 8.1 from microsoft with the media creation tool however it doesn't seem to want to detect the key in the bios so i think that may be since it actually came with windows 8 ( pro).

I can't seem to find any downloads from microsoft with just plain windows 8

I don't have the recovery OS anymore, and i don't want to purchase it them from lenovo since they are lamost charging as much as the actual operating system which i already technically own

 

Before you carried out those steps, did you first check that you had the required prerequisite Windows Updates?
Once you ran Windows Updates, and installed all critical and important updates, and any 'recommended' ones mentioned in these guides, the 8.1 update should have been available from the Store:
http://windows.microsoft.com/en-gb/windows-8/update-from-windows-8-tutorial
If you didn't see the available 8.1 upgrade this guide suggests why that may have been:
http://windows.microsoft.com/en-gb/windows-8/why-can-t-find-update-store