[UW-GIS-L] ArcGIS extensions

[Haldre]

I have ArcGIS set up to work off-site without a hardware key, and it's 
working fine. However, I don't have any extensions available in the 
"extensions" box.  I suspect that this is because the extensions were 
not installed when ArcGIS was installed- does this seem likely?  I am 
particularly interested in installing the Spatial Analyst and 
Geostatistical Analyst extensions.  How do I do this?  Do I need an 
installation CD or is there somewhere I can download them from?  Can I 
install the extensions after ArcGIS is already installed?

Thanks!
Haldre