If you are looking for a help desk that is powered by Microsoft technology then consider NeuQs.
If is written with Microsoft Visual Studio 2010 using C# throughout is can either use SQL Express or SQL Server 2008 full edition. We also have a Cloud based version that runs on Microsoft Azure.
You can download a version that you install on your own hardware, but there is a cost for this. If you want a Cloud based version we have that too and it's free for three.
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