How to hide boot menu/ Grub bootloader?

I just fresh install Zorin OS core then rebooted after installation then the boot menu pops up waiting for me to select an OS the selections are

Zorin OS
Advance ...
Windows bootloader
System setup

Im not using a dual boot however there is a Windows 10 install in my other hard drive.

I dont want that to appear I want it straight boot up to Zorin OS

Ive tried every solution on every thread that I could find
even configuring the /etc/default/grub file then sudo update-grub.
removing those other selection using grub customiser it did not work

I hope I can find my answer here

What hppens if you edit your grub

sudo nano /etc/default/grub

and change the TIMOUT to 0 seconds?


it did not work
it just boot up to grub command line like this


i did not know what to do at that point so I formated the disk and reinstalled Zorin OS.

Last time I saw my grub menu. I don't know why but now i don't see a menu grub only black screen and then a loading Zorin without Logo Zorin and a name zorin what was before.

I missing something? Also wondering with line "BadRam"