You wont get any assistance with bypassing other peoples PWs here. Its against the forums ToS. Which youd know if you read it and didnt just proceed to post this drivel. Ask the person you took the PC from.
+100! If this is indeed your PC how could you forget something that important? If you really did forget the BIOS password then you should contact the PC manufacture for further assistance I sure they will be able to help you for a price.