Can someone tell me how to break my admin password and if possible, change it? I cannot remember my password anymore.
Short of dumping the SAM and running something like Jack the Ripper on it, which can be time consuming, I'd run a Linux boot disc, mount the hard drive, change to the Config directory under Windows->system32(?) and run chntpw on the ./SAM file just to blank it out.
This only works on local passwords though. And if you're asking this for reasons other than stated (personal use on personal workstation?) then the real administrators will know it was tampered with. Domain passwords in Active Directory can't be altered this way.
Also if your system is encrypted or running with encrypted passwords, this technique will render those encrypted items inaccessible.
Of course this assumes you are running Windows...since you didn't specify...under Linux or other OS's it can be implementation-specific (erasing a hash from the shadow passwd file, having to boot OS X's recovery mode to reset the password, etc.)
Are you using Windows OS? If so, there is a possibility to break your password and eventually change it afterwards. All you need to have is your reset cd. This will allow you to reset all your computer settings to default. This includes your admin password. From that you can change your password to your liking. I have found this thread and I believe this would be very helpful for the issue. http://www.techyv.com/questions/i-want-break-my-windows-password