SQL 2008 R2 Named Instance Client Connectivity Issues?

view full story

http://serverfault.com – We're upgrading our software from using SQL 2000 to 2008 R2. Our customers will be installing an update which uninstalls 2000 and installs 2008 R2 under the same instance. So if no instance existed, then no instance name will be set (default). However, the problem starts with the customers which have a named SQL instance. Starting in 2008 R2 (not sure of ones before), for some reason, a client connecting to the server by its instance name is unsuccessful. I'm testing from the Management Studio - if I can't connect this, then nothing can connect. I browse network servers, and find the specific (HowTos)