Clean install Windows 8.1 on Windows 8 OEM device

[evilsatan]

1) Download Belarc Advisor and run it (only if your computer originally came with Windows 8 and you want to extract the Windows 8 product key from BIOS)

2) Scroll towards the bottom in the Software Licenses section, and look for your Windows 8 Product key, you MUST write/type this down somewhere for the future when you make a clean install.

3) Download the Windows 8.1 ISO (according to which Windows 8 came with your laptop, some laptops come with Windows 8 Single Language, some come with Windows 8 Core, and some come with Windows 8 Pro)

To add Language Packs to Windows

4) Download Rufus

Run Rufus by right clicking on it and choosing Run As Administrator

Insert a USB Flash Disk and follow the below illustration:



After the the process is complete and you have copied the ISO onto your USB Flash Disk using Rufus, ensure you have only 1 HDD/SSD connected to your computer while installing Windows otherwise the boot files will be stretched over to the 2nd partition or HDD which is a very bad idea

Restart your computer and boot from the USB Flash Disk, then hit any key when prompted to start the Windows 8 Setup

When asked to enter your windows 8 product key, do not enter your real product key YET, enter the default Windows 8 product key depending on which version you are trying to install: (this is only used for setup later on when we are in Windows we will activate with your actual product key)

Code:

Windows 8.1 Default Installation Keys
Proceed to the partition wizard screen, it is recommended to wipe all your partitions (if you have your data backed up somewhere) or at least delete the first 3 partitions that you currently have (EFI, System Reserved) and the base C: partition, then recreate them again

Windows 8 keys in case you need them:

Spoiler:

Windows 8: 46V6N-VCBYR-KT9KT-6Y4YF-QGJYH
Windows 8 Pro: V7C3N-3W6CM-PDKR2-KW8DQ-RJMRD

After the installation is complete:

1) When you get to the first screen on Windows 8, do not choose EXPRESS SETTINGS but rather, choose CUSTOMIZE

2) Make sure you disable Windows updates for now and turn off "automatically get and install updates for drivers" otherwise you will have Windows update silently install the VGA, Bluetooth, WAN, and other drivers which you don't want! Always stick to the drivers from your laptop manufacturer

3) After you get to the desktop, go to Control Panel > Computer Management > Disk Management, then change the drive letter of the BD-Rom Drive to whatever you want keeping in mind that you will now insert your 2nd HDD so that will probably need to be replaced. Then reconnect your 2nd HDD, then turn on your computer, shutdown, and reboot one more time

4) Connect to your wireless network, then launch Windows Updates from Control Panel. Install all available updates but do not install any drivers or drivers from Windows update; right click on any driver that shows up in the available updates list, then choose Hide.

The only exception is the Microsoft Wireless Router Module, that can be installed but NOTHING ELSE with regards to drivers from Windows updates

5) Reboot your computer after the updates have been installed, then search for updates again and install the 2nd list of updates (if any)

6) Go to Control Panel > Programs and Features > Turn Windows Features On or Off

7) Check the first box which says .NET Framework 3.5 and click OK, when asked where do you want to get it from, choose Download from Windows Updates.

If you get an error message, then check this thread it can be easily installed offline:

Then try this:

Insert your Windows 8 or Windows 8.1 Installation Media, be it a USB Flash Disk or the Windows 8 DVD

Press the Windows + X Button, then choose: Command Prompt (Admin)

Now copy/paste this code in the command prompt:

Code:
DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /LimitAccess /Source:X:\sources\sxs
Substitute X:Sources\sxs with the drive of your DVD Drive or USB which contains the Windows 8 installation

Example:

DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /LimitAccess /Source:F:\sources\sxs

Press ENTER and wait while the installation completes

8) After .NET Framework 3.5 has been installed, search for Windows updates again and install any updates that show up after the installation of .NET Framework 3.5

9) Go to Control Panel > System then scroll down to the end and click on ACTIVATE then click on Enter New Key and enter the product key that is built into your BIOS which you acquired through Belarc Advisor as mentioned earlier in this guide. As soon as you enter the product key Windows will be activated automatically over the internet.

Source