I know some methods.
1. The best and easiest method: Cloce OS and shut down the electricity power of computer. Open your computer box, take out the cmos battery from the mainboard. Then the bios password will be reset to blank. Put it back after a few minutes.
2. Follow some hard tutorials, it is difficult to do. It is better that you are a expert. For example this tutorial: Bypass BIOS Password or Crack CMOS Password? http://passwordreset.org/bios/bypass-bios-password-or-crack-cmos-password.html
3. Use the bios password recovery tool http://www.biospasswordrecovery.com, but that is not free!
So I would suggest you the 1st method. Hope it helps.