|You could burn a copy of this disc and boot from it:|
Using the disc you could reset the password. If you're confident that you did not put the password in incorrectly, you should make sure that you do not have NUM LOCK on. Many laptop keyboards will change the letters iopjklm to numbers if NUM LOCK is on. This could have been the case when you set the password (in which case, you should turn on NUM LOCK when you put in the password), or it could be the case when your computer starts up.
Turning on/off NUM LOCK is usually done by pressing the Fn key and the button that says NUM LOCK or NUM LK. Something like that.
The problem is quite rare, so I won't be surprised if my solution doesn't help you.