Do you have any ideas what I can do with my old notebook?
Linux Mint on it and give it away, maybe kindergarten or an association.
Otherwise, recycling center.
I was even able to sell my 10 year old Medion Notebook for 60 euro on eBay. Although he stopped working and the DVD drive broke out.
I also was able to sell my Lenovo notebook that was from 2012 for 60 euro, both it was no longer working and was completely out of date.
You can get rid of every scrap on ebay.
Otherwise Ebay.
Can you install Linux and see how far you can get. Easy for the experience.
Or you put a small server on it and tinker around a bit. Doesn't have to be anything, just build your own website and see how it works.
Can I install Linux without a USB stick?
Would also go with CD / DVD. Maybe you still have something from a computer magazine. Otherwise you would have to burn one briefly
Sell it for 50 euro.