I am having the same problem. Under Programs-Arcgis-Desktop Administrator-Availability both ArcEditor and Spatial Analyst are registered. However, only ArcEditor is installed. I followed your instructions (as well as the instructions I found in the tutorial) and went to my computer's control panel-Add/Remove Programs-ArcGIS Desktop-Modify-selected the spatial analyst extension. It appears that something is happening but when I go back to Desktop Administrator spatial analyst is still not installed! I tried doing the same thing directly through my installation CD and still nothing. Any help would be greatly appreciated.
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