bios password error

hello friends,

i,m using INSPIRON N4050.... Yesterday, i purchased windows 8. so, today morning i installed windows 8 in my laptop.The operating System was successfully intalled. But, After when i trying to turn On my laptop its shows BLUE SCREEN and automatically restart..i was trying 4 times more to logo on, but, all were failed.. On the 5th time, the message shown in my laptop (ENTER SYSTEM OR ADMINISTRATOR PASSWORD)...I can't log On my computer.... i didn't give any password to my laptop.... SO, please help me to solve the problem immediately...........