After a reinstall of ArcInfo 9.3 (which works fine for mapping etc), the box for all of my extensions is blank. I've checked, and they're all licensed in Desktop Administrator, but not showing at all in ArcMap. Does anyone know how I can fix this please?
The list of Extensions in ArcMAP or ArcCATALOG, show the Extensions that are installed, and is not concerned with whether those are licensed or not (till you actually check on the checkbox).
What seems to have happened is that you must have installed ArcGIS desktop by selecting the 'typical' option. This does not install the Extensions.
What you need to do, is to install the extensions by Modifying the Installation & selecting the 'Complete' or 'Custom' option. If you select the 'Custom' option you can select which extensions to install, while the 'Complete' option install everything.