SQL Server 2008 Workstaions don't see Instance

Installed a new SQL Server Express 2008 Instance on a new 2011sbs server. The install went well and allowed me to add my Instance (SQLEXPRESS) no problem. Everything in the config looks good, but while I can connect to the SQLExpress Instance through the ODBC on the server itself without any problem I can't get the workstations to see the SQLExpress Instance in the ODBC Data Source Administrator. It just doesn't appear in the drop-down. Checked permissions and services, all look good (automatic and running). Logged onto a workstation as domain administrator and same, which would likely rule out permissions? In the surface area configuration I've allowed remote connections via TCP/IP both with and without named pipes. Every time I've tried something different I've re-staretd the services and re-booted the workstations. The only issue I can possibly think of which may be a factor is that the new server is taking over from a 2003sbs server following the standard Microsoft migration procedure and at this moment the old server is still running with an SQL 2005 instance of the same name (SQLExpress). It IS being seen in the ODBC SQL dropdown selection but the new server instance isn't. Could they be conflicting? I tried stopping the SQL services on the old server to see if that may help: When I do so, the instance on the old server is no longer available but the instance on the new server still has not become available.