Dual Boot

[Master Po]

Please tell me what to press on a keyboard to view operating system menu when I turn on a computer?
Before few months I have accidentally press one keyboard button and I see OS selection menu.

Please tell me if you now.

 

[fireberd]

Depends on the brand. F11 on some, F8 on some, F12 on some.
Usually there is a display at power on of what key to press to enter the BIOS and what key to press for the Boot menu.

 

[Megahertz07]

As mentioned by Fireberd, depends on the manufacturer.
Also, fast boot must be disabled to launch Boot Menu.

 

[AddRAM]

If you`re talking about the dual boot screen it should come up by itself, then just use the arrow key to choose the OS you want to use and hit enter.

 

[Schrade]

GRUBLoader won't show the menu if only Linux is installed, and WILL show a menu USUALLY if os-prober has detected multiple OS's.

I HAVE however seen NO menu display AFTER multi OS's are in GRUB.

I think Control, or Shift key forces GRUB to display menu, regardless of Linux only, or multi OS's detected. Thereafter, it will display menu every time.