Computer has been broken

When I try to check my program computer was crashed without crashmessages and now I can't power-on it. How can I reestabilish my computer? Or get files from it?
Help me plz :(/>

p.s CTRL + T\R\S not worked

Most likely you triggered yield protection; if a script fails to yield at least once every ten seconds, ComputerCraft may shut the system down (assuming it can't simply crash the script).

Usually you could restart it simply by exiting the computer's GUI, then re-entering it, but I'm guessing you've gone and made your problematic script the "startup" script, and so it'll just crash again… If that's the case, create a floppy disk with an empty file called "startup" on it, and place that into a disk drive next to the computer you need to fix. Next time you activate that computer, you should find it booted back to the shell.

Disk with startup not helps me.
I write this code to program:

shell.run("reboot")

Then I get floppy from disk drive and nothing is go on.

I restart my world and Computer is alived, thanks!

You can open your system's explorer and go to

/.minecraft/saves/<WhatEverYourWorldNameIs>/computer/<TheIDOfTheComputer>

and then delete the startup file or edit it withyour favourite text editor, it doesn't matter that the file has no file ending.
Maybe you can even post the file so we can help.