I have updated to ubuntu 12.10. Daily I receive notice from the software updater that files are available for updating. When I click on the "Install Now" button, the clock icon briefly shows, then nothing happens. The next day I get the same notice showing the same size of download available. After a couple weeks of this the notice changed to showing twice the size of download available. This seems to confirm my doubts that no updates are ever installed, they merely accumulate.
How do I get the software update function to perform?