Whenever the laptop is from my mother and I just want to gamble on the PC, I have a very bad connection to the WLAN although I connected it via LAN cable what could be the reason and what can I do about it and if the laptop is off I have very good LAN
The devices share the same line. And if one of them uses too much bandwidth, this will also affect all connected devices, as the case may be.
And can I do anything there?
Buy a contract with a larger bandwidth, nothing else. Limit data usage of it.
Make a better contract for the Internet or if you need the bandwidth that other devices do not let surf the net.
Had stolen my thoughts xD
Sounds like your mother's laptop is taking up all the bandwidth.
Either she downloads tons of files all the time, or there are always updates in the background, or she has a bad thing on her laptop. Your mother should scan it. For example with Malwarebytes. https://de.malwarebytes.com/...bytes.com/
Incidentally, you can also see in the Task Manager, whether any programs use the Internet connection.