Are you using windows 7 ?
As the exact way to do it can change depending upon what operating system you are using.
Try this for Window 7
Shut down the Laptop.
As it Boots Up press F8 (pulse press) until you see a Menu.
Now select safe mode.
At the windows login Menu select Administrator.
Hopefully you can then get access.
Go to the Control Panel
Select User Accounts
Select the locked out account.
Shut Down the Laptop
Start it up as normal with the new pass word.
Note : Windows 7 also allows you to create a Password reset disk.
Top Tip : Print this off before you try it lol
Last edited by Mark; 14th Aug 2012 9:54pm. Reason: Added safe modern line