We would like to make use of the MSN Instant messaging service within our domain. Our DC's are both Win2K3 standard Edition and our Exchange Server is Win2K Advanced. I installed the Instant Messaging software from the Exchange 2000 CD onto a Win2K3 Standard machine that is a member server. I understand that Exchange 2000 is not compatible with Win2K3 however I am not using the mail services and thought I would give it a try before re-installing the server I intend to use. Basically, on the Win2K3 machine I installed the software and System Manager. When I go to the "Exchange Features" tab, of the user I intend to use, I click on "Enable" and I am asked for a IM Home Server. The problem is that the "Browse" button is disabled. Is this because of Win2K vs. Win2K3 with Exchange 2000 (possibly)? Or is there a step that I am missing? P.S. Why not use Exchange 2003? For licensing reasons. P.P.S. Why do you want to use IM? Because we are currently using an antiquated version of ICQ Corporate Edition on an old NT4 domain that I want to get rid of and this will be the final step.