can i change the OS on routerboard (level 4 ) with other level 5 or 6 by netinstall ( or other way ) ??

Are you talking about OS or level of license.?
If OS: upgrade via netinstall or another ways
if Level of license. Purchase a new level.

M.

Are you talking about OS or level of license.?
If OS: upgrade via netinstall or another ways
if Level of license. Purchase a new level.

M.

THANK TO YOU FIRST
I TALK ABOUT LEVEL OF LICENSE
I MEAN
IS THE ROUTERBOARD SUPPORT CHANGE THE LICENSE ( RB600 ) ?

You would need to purchase a new license. You can _not_ upgrade license level.
You can get a new license from any reseller or logging in to Mikrotik.com and purchase it.

These should help you with any other licensing questions.
http://www.mikrotik.com/pricelist.php
http://wiki.mikrotik.com/wiki/Most_basic_questions

-Louis

thnx all
where can i get the harddisk id( in rb and x86 ) to purchase license ?

You can get the software ID by connecting via Winbox and going to
System --> License

-Louis

THNX
WHAT IS THE MEANNING OF SERIAL NUMBER OF HARDDISK ? ( ITS USE TO PURCHASE LICENSE )

1. Stop screaming and turn off the Caps-Lock

2. System License menu will show you the SoftID that is needed to purchase the license.