I have a problem entering in the long mode.
The example with long mode, doesn't work, computer gives crash all time.
I've try to make the essential code, and if I use USE32 command, after or before entering in protected mode, the commands doesn't work properly.

Show your code. We don't know what you have done or what example you are using.

you can't enter Long Mode from within Windows so why are you posting your question to the Windows section?

Windows already enters Long Mode if you're running a 64-bit Version, there is no way applications can enter Long Mode.

I've tryed to make my own OS, setting global description table and entering in protected mode, withow any OS. Is not an Windows application or linux application, my application is boothing on the start of computer. I am not using dos or unix. Only bios and hardware function(like processor function, video board, etc.). This things is a part of my os kernel.

The FASM example that doesn't work in my case you will find here : http://flatassembler.net/examples.php

Moved to OS Construction.

are you sure you have an x64 processor? the 'simple' example that Tomasz wrote only requires a 64bit-capable processor and VGA Text Mode (to show the text "LONG" in green). the "basecode" example requires some extra mainboard hardware but those should be present on any x86 compatible system board.

Yes I have, I've already instaled Windows - 64 bit on my pc. Is a real computer.