|Login as another user with admin rights then right click on "Computer" in the start menu and select Manage. Then go to local users/users and right click on the administrator account and click set password. |
If you only had one account on your computer and forgot the admin password then you will need to hack our computer. We can not tell you how to hack on this forum so you will need to google how to hack an administrator password or look for key words like rainbow tables and kon boot. Hope it helps.