I beleave My graphics card has is broken as after a while the monitors turn black on both linux and windows but not on the bootable manjaro usb i have so can anyone tell me how to disable the graphics card and use the motherboards graphics?
If you have installed the proprietary nvidia driver, then you need to remove it and install the free drivers if not there. Here is a manual:
I installed the free driver and removed the gpu removing the gpu fixed my windows install but linux is now giveing me failed to start simple desktop display manager
remove the nvidia config:
sudo rm -v /etc/X11/xorg.conf.d/90-mhwd.conf
You probably forgot to follow the crucial step told by megavolt, remove the nvidia driver first before anything.
//EDIT: and to type commands now that you have a broken desktop, you can go to a TTY with [Ctrl] + [Alt] + [F3] then login with your user and you can now type commands.