. Help me how to unlock my laptop. I have change it several times but unfortunately I forgot which one and I have tried several possible password I just don't have any luck.
Thanks!

Do you have a set password for the Administrator account?

At the welcome screen, hit control+alt+delete, then type in Administrator, leave the password field blank, and hit enter.

If that doesn't work, there are some password recovery tools available in Linux that you could try. Ubuntu has a pretty good live cd that will let you boot into Linux from the CD.

I don't know what operating system you have, but I can tell you that in newer versions of windows you can only try three times to unlock it. After that, especially in XP and VISTA, regardless of whether you get it right it won't let you in. You have to chose the shut off option and try again.

Hopefully you do not have the administrator's account setup as your own, so doing the above advice is worth while. You can then get into user accounts - but the only way to change the password from there is to know the old one first. Fortunately from the Admin account you can see and access all users (should be able to anyway) if you fail to remember your password.