[Q] Is there a way to somehow backup current windows state?

Once you have Windows 10 Pro installed and activated, you have the "Digital Entitlement".
Digital Entitlement means that you can re-install Windows 10 in the same computer anytime you want and as often as you want.
You won't need a product key to re-install, and activation will be automatic.
You won't need your Win 8.1 Pro disk anymore.

You can backup your Windows 10 Pro image to an external hard drive, and you can use it to restore the system if something happens to Windows 10 Pro and you cannot fix it.

The above is just general info.
There are tutorials to show you how to do that.

roostaamir said:

Thanks for your quick reply
If you don't mind me asking (since I don't have windows 10 yet), how can I work with this "Digital Entitlement" feature?
And how can I actually backup the windows to an external storage?

Digital Entitlement is automatic once you have Windows 10 installed and activated.
Any time you re-install Windows 10 Pro in the same computer, digital entitlement comes into effect automatically. You will not require to enter a product key and after re-installation, activation will be automatic.

Windows 10 has a built-in program called System image Backup.
When you run it, it will first find out where the backup file will be saved to. If you plug in an external hard drive, it will recognize it and it will start copying an exact image of the system at that time to the external hard drive.
If you need to restore the system, you will plug in the external hard drive to do that.

In this Tenforums.com, the "de facto" program to do image backup is Macrium Reflect. People will swear by it.
Personally, I use the built-in program which has worked for me and never once failed me.
You will decide which way to go.