It sounds like the Power on Password has been set in the in the BIOS. It is difficult to do this without knowing that you have done it and so I am at a bit of a loss as to how you got there. Unfortunately that password is designed to turn Stolen ThinkPads into scrap.
If you take it to an IBM Service Centre or Authorised Dealer they MAY be able to help you but, if I remember correctly it won't be cheap, as it usually needs a motherboard swap.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix notebooks/laptop pcs.