Alright… so please correct me if I am wrong…
You start your system… you see the grub screen … you choose the top most option to enter Linux Mint
However, it shows some messages on the black display and then hangs there?
If that’s the case and you have Nvidia graphics and then it is the drivers issue.
yes, you’re right.
how can I solve this problem?
Try following the suggestions here:
Thank you 
sudo : gedit: command not found
You may need to install gedit
or
you may have a PATH problem
or you could use another editor
That’s because Linux Mint doesn’t come with gedit, it uses xed I think. But still, you can install gedit and then follow the rest of the tutorial.
The grub screen will always be there.
Are you not able to log in?
Yes, I can log in.
every time I’ll login through the grub screen?
You login via the login screen. GRUB is there for presenting you various boot options, in case you need it. Normally you don’t need it.
I’d set GRUB timeout to a low delay, say 2 seconds. That is short enough to not bothering much, but still gives enough time to press a button, and interrupt boot sequence when there’s a problem to fix.
Do this with setting
GRUB_TIMEOUT=2
If you are absolutely sure you won’t need GRUB menu, set the timeout style to hidden. I see on your photo, you already did this.
But note, that if you edit /etc/default/grub (and save changes to it), you need to run
sudo update-grub
in order to make changes have an effect.
but still see this window before log in screen. and after log in the window is smaller than the screen
You can ignore this screen if it is not stopping you from loggin in and using your system. It gets displayed for a couple of seconds then goes away. With some firmware updates in the future, these error messages will go away.
Now that’s a problem. This is likely because you have disabled the graphics card.
How can I solve it?
1- can I use nvidia driver from driver manager only? and would this solve the problem or no?
2- should I do this from grub list or with normal login ?
Don’t touch the grub unless required. It serves the purpose of giving you the option to boot into recovery, an older kernel and if you dual boot, into other operating systems.
Try installing the drivers and see if it works better.
after installing nvidia driver and restart.
I still can log in but the window is small and see this before log in
In your grub config there’s a line
GRUB_CMDLINE_LINUX_DEFAULT
Edit this to include loglevel=0
So it looks like GRUB_CMDLINE_LINUX_DEFAULT="quiet splash loglevel=0"
Run update-grub, and reboot.
Does it behave more nicely?
