Reverting to an older password, calling a password recovery service, having another person log in who has administrator rights and changing your password, and performing a search for password recovery software are all options for getting to the desktop. These instructions work for Windows Vista, but other operating systems vary.
Use Microsoft System Restore to take your computer back to a point in time when it had a password that you remember. Use System Restore by pressing F11 repeatedly after rebooting the computer. Click "Advanced Options" and then "Restore your computer to an earlier point in time." Think of a date when the computer had a password that you remember, and restore the computer to that point. Then, reboot your system, and enter you password.
Have someone else log in to the desktop who has administrator rights. After the desktop comes up, click "Start" and "Control Panel." Click "User Accounts and Family Safety," and then click on "User Accounts." Choose "Manage another account," and choose your account. Click "Change the password" and enter a password you want to use. Add a hint to help you remember it later. Click "Change password" to complete the process. Restart and log in with the new password.
Local computer repair stores frequently provide password recovery services for a fee. The Internet also has software available for password recovery, but the security issues with many of these programs make this the least viable solution.