At the password screen press these keys: ALT+R, it will show a message and the date, ex. 2017/02/11. Post here the date to get the password.
Thanks for your reply. but I tried the method you mentioned. My PC Asus expertbook B1500C and bios version is 304. so alt+R keys on password screen don't work I removed the bios battery from the motherboard. Still the password was not reset, only the datetime was reset. Also I couldn't find the jumper to reset. is there any other method?