PASSWORD

I HAVE A GATEWAY2000 I BOUGHT FROM A FLEA MARKET AND IT SAYS, WHEN THE BLACK SCREEN COMES UP THAT REGISTERS THAT EVERYTHING IS WORKING OR NOT (KEYBOARD, MOUSE ETC..) IT SAYS THAT I NEED OT ENTER IN A PASSWORD BUT SINCE I BOUGHT IT FROM THE FLEA MARKET I DONT KNOW WHAT THE PASSWORD IS CAN ANY BODY HELP ME OVERRIDE THIS OR GIVE ME SOME KINDA HELP AS TO WHAT I SHOULD DO ABOUT IT?ANY HELP WOULD BE GREATLY APPRECIATED THANKS