Dear Behnam,
Are you absolutely sure that your console cable and terminal program are working? Have you tried them with some other devices?
Make sure they are all working and the terminal settings are also okay: perhaps 9600 8 N 1 is the default, 115 8 N 1 is what some are setting past the switch boot in order to get faster output. Flow control must be disabled both hardware and software, else you won't observe any output at all. If you are observing garbage symbols rather than readable output then you may check the terminal speed, if you see nothing then it could be due to flow control or bad console cable.
I'm saddened to tell you, if you are absolutely sure that your cable, your terminal program and settings are correct, then you are most probably having a switch with a hardware issue without any chance to restore at all.
Those switches that can't load any OS due to wrong firmware file or any other configuration error are always fixable through the loader> prompt or switch(boot) menu, however if you can't reach any output at all, your bios is most probably corrupted and the switch is not repairable.
