In your terminal, try (without quotes) "sudo apt-get update", and then see if the Software Centre lists available stuff. If not, check your sources.list. Press Alt-F2, enter "gksu gedit /etc/apt/sources.list" (or maybe for Ubuntu it would be "gksudo gedit /etc/apt/sources.list") in the run application dialogue box, and then check out, and if need be, edit your sources.list (IE, if some listed repositories are commented out with a "#" sign before them, remove the number sign, save the file, and then run "sudo apt-get update" again).
Last edited by mark_alfred; 11-01-2009 at 05:24 PM.
Reason: possible differences w/ Ubuntu -- specifically the sudo stuff