I do not remember the serverauthentication password, so I am using windows authentication. I am not able to do anything.

I do not remember the serverauthentication password, so I am using windows authentication. I am not able to do anything.

You need to fulfill the following requirements:
In this case, when connecting using Windows Authentication, you can check if you have any permissions (check the Logins sub-section of the Security section in the SSMS. If the NT AUTHORITY\SYSTEM is shown there, you can add the needed database. Otherwise you need to bethink the sysadmin login & password.