If you lost your password for your Windows 7 system and you do not have a password reset disk, there is no supported fix from Microsoft. With that said, there are quite a bit of 3rd party tools to recover the admin password. While they may not be supported by MS, they do work. Some are free, some are paid. I have used a few of the free ones without any issues.
With these 3rd party tools, you would need to be able to download an ISO image and burn it to a CD. you'll need to get access to another computer.
If you are able to log on, you can always change the password by accessing the Computer Management console --> Users and Groups --> Users, find the user account and force a reset of the password.