When My laptop (toshiba m200) starts, it display" password" But I did not enter any password and canot go to motherbord bios or canot boot from any disk. Need solve this problem.

You need to remove the main battery and then the laptop has to be partially disassembled to locate and remove/replace the system battery, That will clear any BIOS paasword and reset the whole BIOS. I recommend this only to the technically and mechanically inclined. Finding and downloading the Service Manual from the manufacturer's website would be where I'd begin.