Hi rebesta,
Welcome to the HP Forums!
I would like to take a moment and thank you for using the forum, it is a great place to find answers. For you to have the best experience in the HP forum, I would like to direct your attention to the HP Forums Guide First Time Here? Learn How to Post and More.
I see you have forgotten your administrator password. Here is a Windows document that may help. What to do if you forget your Windows password.
One of the last steps is to reinstall Windows, before doing that try this step.
Boot into Safe Mode and create a new administrator account.
Now restart and try logging in with the new account. If you are successful, then delete the original account you were having the issue with.
Here are links to document to assist you with the recovery process if neccessary. Performing an HP System Recovery (Windows 7). While doing the recovery process, you will get an option to backup your personal files, if you have not done one yet, I suggest you do it now to prevent losing your data. Restoring Files that were Backed Up Using HP Recovery Manager (Windows 7)
I hope this has helped.