Upgrade to 13.04 was not successful. Gstreamer not working. What do?

I finally decided to upgrade to 13.04. In the middle of the installation my computer froze completely, and so I decided to force quit. I log back on, and notice that the login says 13.04, but not everything was updated. So I run the software updater. Some of the stuff gets updated, but not everything, I suppose. I try to run Rhythmbox, but it says that it's not able to form playback, and that the Gstreamer was messed up, and to please check installation. I don't know what other bugs maybe running. That's just the first I've encountered. The software updater won't let me update anymore because it says the updates need authentication.