You can download a program on another computer with internet access and then you can burn the image with nero, poweriso, ultraiso, etc.
when you get to this page: http://ophcrack.sourceforge.net/download.php?type=livecd
you are going to get 2 options depends if it is windows Xp or Vista you can check on the label on the bottom of the computer. it takes a while to download but after it finishes burn the cd and use it on the laptop.
restart the computer and press f2 or f12 to go to boot order, change the order for the cd to start first (move it up) with arrows or f5-f6. press the esc key on your keyboard one time only and select save changes and exit or save and exit, confirm and laptop will restart
insert the cd and again restart computer run the program and it will give you all the passwords and users on the system, write them down and try to access with that information.
go to control panel-accounts-change account-select account-change password- enter obtained password and type your new password (twice)-save-go back to do your things.

if it worked for you don't forget to rate me
thx