I have an IBM Thinkpad T20 that i planned to keep as a spare, but my cousin somehow managed to lock me out of it by entering the wrong passwords. Now when i turn it on i only have to touch one of the keys and an alarm noise starts.
How can I gain access again?

Sorry but we can't help you get around computer security measures because we don't know that you are the owner nor can we take your word for it. Even if you are the owner another reason why is that we can't control whether or not someone else comes along later and uses any such information to hack into a computer that isn't theirs. Think about it from the stand point of that it could be your computer in the wrong hands. Comprende?

If you want the legal mumbo-jumbo from our TOS here is the relevant section:

11. The following is unacceptable behaviour which may lead to you being banned from using the Website: Please follow the next set of rules VERY CAREFULLY, going against some of the following rules can result in you being permanently banned from the D-A-L network.

d) Discussions that encourage, promote or provide information about illegal or criminal activities (including pornography, explosives, weapons, drugs, programming viruses, computer hacking and copyright infringement).