yesterday rb 133 stopped fuctioning even its disappeard from winbox i connect by cable console and found demo expaired ,howcome! after many searching saying that LICENSE key expaired. reinstall os allpackage 2.9.51 by netinstall as said in mikrotik. now i can see and inter the rb by win box but its 24 days LICENSE why how can get my LICENSE key back

The same happened to me after a power outage. Contact your dealer. They can get you working again.

You need to log into your Mikrotik account and retrieve the license key for that RB133. If you use a dealer or distributor, they can do that for you. Then paste it back into the 'System License' menu.

Tom

yes, and to avoid that in the future, always keep the bootloader up to date. your problem was caused by a problematic bootloader version