MS-ACCESS and performance

I need urgent help !
I have developped a multiuser database application with plenty of
master-detail relationships.the application runs within a WinNT 4.0
network.If one starts a single application local the performance is good but
when i start an application via network the performance slows dawn
dramatically (even browsing is not acceptable).I am using Delphi 3.0
professional,MSAccess95 BDE 4.51 and the most applications uses TTable
components.Can anyone help ???????????