In
VB 6.0 when I use this code, it works OK so try.I believe that help you
Conn.Open "Provider=MSDORA.1;Data Source=YourServer;" & _
"DNS=Pubs;User Id=sa;Password=;"
That is for Oracle, if you want to do it with Microsoft driver, you have to change Provider and DNS.
Also, you have to create DNS in File DNS for each driver.