First q. I want to know I can create password in dos not in bioss
Second there are dos password in my PC in dos not in bioss how can I delet it

I used to work a lot in DOS and was one of the last to move on to a Windows OS. Maybe I'm just old and forgetting things, but I don't recollect being able to put a password in DOS unless I wrote a .bat file or editted the autoexec.bat (maybe config.sys).

It is more than likely in the BIOS and removing the battery or jumper should clear this.

To check that there isn't a .bat file being run at startup. Drop to DOS (Start, Run enter "cmd" press [return]).

Type "cd \" [return]

Type "type autoexec.bat" [return], there should be very few if any lines in this file. If there are lines let us know what they are.

Type "type config.sys" again there should be few if any lines in this file.

first q. i want to know i can create password in dos not in bioss
second there are dos password in my pc in dos not in bioss how can i delet it

As Colbtech said there is NO way in DOS to create a password. You may have been using a third party program that ran when you boot the machine that required a password. If that's the case then that program is listed in either autoexec.bat or config.sys. You have to identify the programs and see how to manage users within it.