It might bee that your graphics card is not supported with thee latest proprietary drivers. I haven’t checked myself, but it might fall under one of thee GPUs not supported by the latest drivers. Please see this announcement post by @philm
You can try the very old unsupported Nvidia 340 drivers. Basically follow this guide after you have made sure you have the supported kernel installed and running (this will only work with kernel 5.4 and/or 5.10, other kernel are not supported with that method). For the kernel, go to Manjaro Settings, and install kernel 5.4 this should be good for your old computer. If it is already installed it’s already OK go to next step, click the link and read the whole post by philm.
Then open a terminal, and do as instructed, then reboot and you should run the old Nvidia drivers.
If it goes wrong and you can’t properly boot to desktop anymore, you can restore the system but you’ll need to be able to access the forum for help from another machine.
Ok. I have selected all! Sorry for asking you with every step. I have never ever done such a thing and that gives me flashes and shock and all together. Fingers crossed
Unfortunately Copy Past to the terminal does not work. I have no idea how to get the next step into the terminal sudo pacman -S $(mhwd-kernel -le then comes this straight line - No idea where to find this.
To paste to terminal you can click with right button of your mouse, or you can CTRL+SHIFT+V (at least on KDE desktop this keyboard shortcut works, but right click should work on all desktop environment I think).
You can go back from this installation from the black screen, you have to switch to another TTY with CTRL+ALT+F3, and remove the packages you just installed which broke your Manjaro.
In theory, it should be:
sudo pacman -R nvidia-340xx-dkms
sudo pacman -R lib32-nvidia-340xx-utils
sudo pacman -R nvidia-340xx-utils
I’m not 100% sure of package names but that should be it.
//EDIT: when you switch to another TTY it should ask you to login so enter the username, and then the password, and you can type the commands one by one, make sure to type exactly without mistake (if I didn’t make mistake myself )