this is a very advanced solution but please DO NOT pursue this if you do not have any hardware background as it could cause damage to your machine and yourself
- remove the battery
- remove the HDD
- open-up the memory bay, remove bottom ram and keep the upper one
- now search under the lower ram position and check for two little pins labeled B500, you have to manage to touch them together with a metal flat screw driver as you plug your ac adapter and start the machine
and now when your lap boots it will loose the pass, turn it off
remove the pc adapter and put back the ram and HDD.