So I had an old PC with Windows 10 on it. I decided I wanted to install Linux on it, as I had a few weeks ago with an old laptop which runs fine. I installed Ubuntu Server fine but then decided I wanted the version with a UI. So I installed Ubuntu via a USB it went through the process of installing until it done a restart. That's when the problem occurred. I tried to access the boot order to change it back and I couldn't access it, nor could it boot up into Ubuntu anymore. I've spent absolutely ages trying to fix this machine that runs perfectly fine but fails to get past the HP splash screen. Does Ubuntu change the way you access the BIOS or something, or have I somehow corrupt it as I absolutely cannot access it. Whenever I use any F key it leads to black screens with text as shown in the image here: https://imgur.com/a/FwR1cRf
So does anyone know a possible fix? I swear I've tried absolutely tons to fix it, yet it never gets past the HP logo or that black screen with text.