Gestalt needs SQL Server to run. Preferably SQL 2012 but it will also run on SQL 2005/2008 and runs with SQL Express of any of these versions too.
It therefore requires a Windows Server base machine to run on, such as Windows 2003/2008/2008R2/2012/2012R2.
Gestalt typically required 8GB of RAM on the server to run. A 4Gb server might be suitable if Gestalt is the only application running on that server.