Restart computer and wait for the password request to display. Press Ctrl, Alt, Delete keys twice. A new log in screen will appear. Erase user name(top box) type Administrator in it's place. Erase password(lower box) and leave that box blank. Press Enter. A welcome screen will display and you will automatically be signed into a NEW user account with administrative powers.
Click Start, Control Panel, User Accounts, User Accounts again.
The next page shows all user accounts on that computer including the new one you just created.
Click on the account you wish to change/remove password and press Enter. Follow any remaining instructions.
Note: Once logged into your account, it's best to make a password reset disk. I use one of those USB Flash Drives for mine. To do this...
Insert Flash drive, Click Start, Control Panel, User Accounts, User Accounts again, click on your Account, and under related tasks...Click Prevent Forgotten Password. Follow instructions. Once reset disk is made, no matter how many times you change your password in the future...you'll still be able to get into your account Via the password reset disk.