Windows 8 / 8.1 bootable CD?

I have an query regarding.iso file of windows 8/8.1 basic. I have Lenovo laptop in which windows 8 was pre installed and after a couple of months it's been upgraded to 8.1. After purchasing this laptop I found that like my previous laptop with win7 there's no key file mentioned at the back of the laptop. But, still I managed to get the key for win8.1 through belarc advisor. Now my question is, if I want to format my laptop in traditional way through bootable CD, then from where I will get the windows 8.iso file? As, in microsoft.com no where I found the downloading option for windows 8 / 8.1 like windows 7. Now, I searched in google, How to make a bootable cd for windows 8/8.1. I followed the steps as it is mentioned in www.tinyurl.com/92bxels… But when I'm running the software and trying to put my key file it's saying it's not applicable. So the main question is, from where I will get the.iso file for windows 8 OS, and will the key file of the present upgraded windows 8.1 work with that downloaded windows 8/8.1 os?

I don't know whether I have explained my question properly or not. But, if anyone understood my query, then can you help me in this regard?

The OEM product key for your preinstalled OS is specific to that install…
If the included manufacturers recovery software allows you to create install media on flash drive it will work with that.

Trying to clean install 8 or 8.1 even if you used magic key finder or belarc advisor to find the product key, the product key will not work…
Unlike installing an OS of old when the product key is know you could just use any installation disc with matching OS ie Vista, XP, Windows7 and matching edition Basic, premium, Professional, Enterprise etc etc ect.
OEM Preinstalled 8 or 8.1 is not like that.

This is some thing i have done, it may be of use or not…
Frustratingly the included recovery management software on my Acer V5 windows8 would not allow me to create recovery media or copy files to recovery drive.
Message "Files are missing"

I wanted and needed a future backup should the hard drive ever fail or windows becomes corrupt.
Running the inbuilt windows8 Reset or refresh, same thing Message "Files are missing"

However accessing recovery at start-up then running reset works.
After reset at the "Microsoft terms and conditions"… I shut down computer…

Booted to bios and changed boot to "Legacy" and CD first in boot order.
Booted from (Free) REDO backup and recovery CD.
Created a total system image on external derive (Only used space is backed up, the image is small).
http://redobackup.org/

Booted back to windows 8
Installed just the two minimum updates required to make 8.1 available in windows store. ( Windows updates KB 2871389 and KB 2917499 )
Updated to 8.1.
At reboot on the "Create log in account /User name"
Shut down computer
Create system image backup…

Next got a large capacity USB flash drive. (64GB)
Used yumi bootloader (Free) added REDO ISO to flash drive.
http://www.pendrivelinux.com/yumi-multiboot-usb-creator/
Added http://www.partitionwizard.com/ ISO (For future use if a replacement hard drive is larger than original)

Coped Windows8 (Factory) backup and windows 8.1 to a new partition on my bootable flash drive…

How To Do Clean Installation Of Windows 8/8.1: http://www.wiknix.com/clean-installation-of-windows-8-1/