Broke yum when upgrading from FC4 to FC5
I upgraded from FC4 to FC5 using CDs I'd burnt. Everything went well with the installation, and all the data previously there was preserved. The only problem is that yum still looks to the FC4 repositories for updates, and gives me a "failure" message saying that it has tried all the mirrors and cannot find anything for FC5. How do I remove the current settings, and do a clean install of yum?