Trouble Installing Spatial Analyst Extension

Discussion created by ejbrodsk on Jun 18, 2011
Latest reply on Sep 12, 2011 by JSwain-esristaff
I have a single use version of ArcGIS 9.3.1 and I'm trying to install Spatial Analyst.  I went into Desktop Administrator, followed the instructions and checked off Spatial Analyst, and then it told me that the extension was registered and ready for use.  The help menu tells me to go into ArcMap, go to Tools>Extensions and check the box next to Spatial Analyst, but no box comes up.  Am I missing a step? 

Any help with this issue would be much appreciated... I cannot go any further with my current project until I have this extension installed.