The instructions at http://www.symantec.com/business/support/index?page=content&id=DOC3484&actp=search&viewlocale=en_US&searchid=1322629124880
http://www.symantec.com/docs/DOC3484
Do not explain where to get the Windows Mobile Device Center 6.1 application. It is very unclear on Microsoft and on Symbols support website where to get this. The product documentation with the MC75a still says download activesync 4.5 from microsoft.com
Navigate to http://www.microsoft.com/download/en/confirmation.aspx?id=3182
Download drvupdate-amd64.exe which is Windows Mobile Device Center 6.1 Vista x64. Their has not been a newer driver downloaded.
If the Machine is WIndows 7 x32 the download the other driver WMDI 6.1 for Windows Vista(32-Bit)
ActiveSync 4.5 will not download on a windows 7 desktop
After the application has installed then connect the barcode scanner