Fedora core 3 is pretty ancient at this point. So's redhat 9. You're going to have big problems and very little benefit if you try that, I think.
You're better off backing up your data and doing an upgrade install. You're also better off going to at least fedora core 6 or 7, if not 8.
Note that an upgrade install shouldn't/doesn't entail a format, but you should still back your data up before you try it.