How to upgrade Windows 8.1 Pro to Windows 10 (free)?

First of all, have an older laptop with 4 GB of RAM. Old but running.
Is only intended for surfing and emails.

Since Windows 7 was completely discontinued and no updates were made, I did not get some things installed.

I now have Windows 8.1 Pro on it.
You can read on the net that you can upgrade from Windows 7 or 8 to 10 for free.

I've tried under 7, and now under 8.1. No matter what I click, you should pay.
If it only works under 7 and not 8.1, that wouldn't be a problem either, because I have 7 here.

Unfortunately, I don't know my way around very well, can someone please explain how to do this, preferably with a term or even a link, what I have to download and install?

You get the "media creation tool" from Microsoft and use it to generate the required ISO file for a USB stick or DVD. From this medium you then start the setup.exe under Windows.

https://www.microsoft.com/.../windows10

see my answer to another question

Best to install Windows NEW. Is the cleanest solution.

Your key also works with W10

Thanks. I downloaded it, preparations are in progress.
But how exactly does it go on? I load the file onto a stick, how do I proceed? Can't I just click "upgrade this PC" and that's it?

Make a backup of your most important data (pictures, documents, videos, etc. Pp.) And install Windows cleanly again

Your Windows 10 Pro is activated by your previous Windows 8.1 Pro license.

Microsoft provides the Media Creation Tool for creating an installation medium, which you can download here → https://www.microsoft.com/.../windows10

Yes exactly, e.g. Play on the stick with rufus. Then you have a normal USB drive, when it is finished, you will find the setup.exe in the root directory. Just start it and answer a few questions. And then wait. Waiting. Waiting. ^^

The computer then starts up again from time to time, which is completely normal.

If everything went well after all the waiting, then you have Windows 10 on it.

I completed the process, BUT since I don't have a Windows 7 and Windows 8.1 license key, it doesn't work.
Do I have to buy one now, or is there another option?

The license from the existing old Windows is automatically adopted. You don't actually need a separate key. I only know of exceptions from computers that had a volume license.

Yes, I don't currently have one. My Windows is not activated.
I have now bought a key for my 8.1 Pro as a download for 9.90 euro from a shop and Windows is now activated. Now just repeat the process.

Thanks! Everything went perfectly. After I bought a license key and activated my 8.1 Pro, I was able to upgrade to 10. Now runs under Windows 10, find it much smoother.