Hi:
Here is a link to download a 64 bit OEM W8 ISO file, which should work with the product key in the BIOS.
It has a limited number of downloads per day, and as I type this, it is not currently available for download, so you will have to check back later. I would check several times a day and you may have to do this over the course of a day or two.
https://docs.google.com/file/d/0B0W9PBigPy94aVJWSndyTFNFMzg/edit?pli=1
Then use this tool to make the ISO bootable onto a DVD or usb flash drive (4 GB).
http://www.microsoftstore.com/store/msusa/html/pbPage.Help_Win7_usbdvd_dwnTool