Asus tells me that on my laptop (Asus S440CA,Intel Core i3-3217U CPU @ 1.80 Ghz 6GB RAM) there is no dedicated partition on HDD for factory restore, this function is in BIOS, which doesn't tell me anything.
Rgds.....
I would say you've been misinformed. I own an ASUS K75DE that originally came with Windows 8 Core factory installed. It had a factory installed recovery partition with the factory image of the factory install. I needed a 16 GB thumb drive to create the Recovery drive with the "copy recovery partition from the PC to recovery drive". With that drive you can do a reset and restore the factory image. At least that's what I was told by ASUS. It didn't work for me but that's another story. I had swapped out the factory hard drive for an SSD.
Your Windows 8 product code is embedded in the BIOS, maybe that's what they were referring to. My TechNet 8.0 ISO's read it out automatically during the install and install Core automatically without prompting me to enter a product code. My embedded code is for 8 core. If yours is for 8 Pro that's what will be installed, assuming you have unaltered official Microsoft install media.
I've moved on to Windows 8.1. My TechNet 8.1 ISO ignores the embedded 8.0 code and prompts me to enter one. I could install with one of the generic install codes and then activate with my 8.0 code but I just use one of my TechNet 8.1 codes. I have them so I use them. If your PC came with Core and your installing Pro you'll need a valid legal 8 Pro product code.