Thanks, you better change it then reset it so that you will be access the Computer immediately. Power on the computer and when you see the Logon Screen where you are asked to enter the password, click the mouse somewhere on the blank space on the blue screen and press Ctrl+Alt+Delete two times (or maybe more) on the keyboard, a classing login window will pop up with two boxes, type in "Administrator" (without quotes) in the username box and press enter without entering the password. The system will boot into Administrator's account.
Now, right-click the "My Computer" icon on the Desktop, select "Manage" from the drop down lists, once it's opened, click "Local Users and Groups", again open "Users" folder, the existing usernames will be displayed with the username you've forgotten password on the right-pane of the window. Again right-click your username and select "Set Password", confirm by clicking "proceed" on the pop up windows and type in your new password (no problem, the old password should also work). Click "Ok" and close the window, now logoff and log back with the password to your user account (or simply restart your computer and login with the newly set password), it should work without any problem.
If the administrator account doesn't accept the blank/empty password, you'll need a tool such as OphCrack etc..etc..
Note: if you've encrypted any partitions or file or folder when you were on the computer with the current forgotten password account, then all encrypted files will never be able to opened, but if you don't know this meaning "encrypt", forget it, you better ignore than messing with your files and folders.
But if you know what is file encryption and have done, then try to change them back to default file system from the administrator's account or else, you better wait for my next post if in case you need them.
Let me know when you are done.
Thanks for using FixYa.
on Mar 16, 2015