The help files summarize this. It is tedious. I would advise you to search the forum for articles on removing security or removing workgroups. I would also try it a couple of times before committing everything to a secured database.
Basically, you have to create an empty database.
Then give the Admin account of the old database full rights to read everything. (I say it that way because normally I make my Admin account brain-dead as a security measure.) Just to be sure, in the Tools >> Security >> Accounts dialog, find the Admin account and clear its password.
Use C:\{windows directory}\system32\wrkgadm.exe (Run option from the Start menu) to create and to join the new workgroup. Create a new workgroup file with the same filename and in the same directory as the new database. Location of the workgroup is actually just an option, but this way makes it easier. It also might be easier if the new database ISN'T in the same directory as the old one.
You will automatically be the Admin account because that is the only account in a new workgroup. Open the database's Tools >> Security >> Permissions dialog. Give Admin full access rights for all new objects in each object class. The object to select is always in angle brackets, like '<new query>'. Don't forget that in this dialog box, there is a "database" object that has rights, too!
Now start importing everything from the old database file, starting with tables. When you are finished importing, the new database is the unsecured copy of the old one.
