I got it. It took a while but I got it. It seems that Access is different from other database engine for passing the password to the connection string.

Try this one:
adoConnection.Open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=c:\libtax 1999\libtax 1999.mdb;Persist Security Info=False;Jet OLEDB:Database Password=blah".

Look at the article ID Q191754 in the Microsoft knowlegde base for more details.

Please, I will sleep better if you confirm that it is working (I tried it with Access 97 not 2000).