I'm sorry because my english isn't very good, I hope you're able to understand it. I'm using arcgis 9.3 right now, but when i try the Tools dropdown, then extension, there are no extensions listed. Do you have any idea how to solve this problem? I want to use the network analysis extension to finish my project, please help me.
I have experienced the empty extension list on a workstation with extensions installed. If memory serves me right, I did a repair on the registry with the ArcGIS Desktop installer and that fixed things.
I think it was:
msiexec /fum setup.msi. A complete uninstall/reinstall would have worked as well.
Perhaps the extensions you're interested in aren't installed on the machine? ArcGIS will only list installed extensions. You can add them by visiting the control panel, 'add/remove programs', selecting ArcGIS and clicking 'change' which should allow you to install new extensions (you'll need the installation media to install the extension).