Wifi Problems with the Pi

What is the problem?
My Brother recently changed our Wifi since then my Pi with Octoprint on it will not show up on the Router or even boot. I have tried everything I could

What did you already try to solve it?
I tried to reinstall the OS

Logs (syslog, dmesg, ... no logs, no support)
Cant get them

Additional information about your network (Hardware you are trying to connect to, hardware you are trying to connect from, router, access point, used operating systems, ...)

If you want our help, you will need to provide more details. What model Pi? What version of the OS did you reinstall? How did you configure that OS with your WiFi credentials? Details on what your brother changed (i.e. what was the old stuff that worked, what is the new stuff that doesn't)?

Can you temporarily connect the Pi with an Ethernet cable? We don't need the printer connected so you can move the Pi. This may allow us to capture some additional troubleshooting information.