A couple of customers have emailed me recently saying that they have inherited databases from other people, and they can't get to the database window to make any changes.
Now, assuming the database isn't an MDE file, and the previous developer didn't tightly secure it using the User-Level Security Wizard, you should be able to get to the database window by simply bypassing the startup routine.
If you recall from Access 103, you can specify a startup form and even hide the database window in the database setup options. You can even create an AutoExec macro that runs on startup too.
If you hold down the SHIFT key when you first start your database - as soon as you double-click the icon to open it - this should bypass the startup options and bring you right to the database window.
If not, then the previous developer might have taken additional steps to secure the database. But, this simple solution will get you into 99% of the databases you're going to come across.
If this doesn't work, another easy solution you could try is creating a new, blank database and just importing all of the objects from the old database. You'll get all of the tables, queries, forms, and reports (and macros/modules too if you select them) but you won't have any of the database properties, such as the startup options. Just don't import the AutoExec macro if it exists.
Hope this helps.