Just remember this, and your time here will be nothing but lollipops & rainbows:
1) The people helping you(with rare exception) didn't write the system you're having trouble with.
2) Anyone using FC has been through what you're going through, and they lived to tell the tale.
3) Any replies are done out of the kindness of the poster's heart, and there's no reason not to be appreciative for that.
That being said, we all get frustrated. We's cool, if you's cool. Cool?
RE: your firefox prob
If you want 1.5, you're going to need to do a manual install OR upgrade to FC5. FC4's repo's only go up to 1.0.8. So, if you want that, what you need to do is to download the repo from Mozilla, uninstall your current version, and install the rpm that you downloaded.
First, uninstall the version that came with your install. "yum remove firefox" should get rid of your official install. Then find out if you have any more versions floating around by running "rpm -qa | grep firefox" If you have any left, uninstall them using the rpm command "rpm -e packagename", since you didn't install it via yum, you can't uninstall them via yum
You good now? No more Firefox on your system? Install the new version now:
rpm -Uvh firefox-packagename-buncho'numbers.rpm
That should give you a fresh install of the firefox version you downloaded.
Then you're going to need to point your applications to it(telling them to open items in FF, if you want to use it as the primary browser). You can do this through the Control panel in your Desktop menu.
Let us know if you get stuck, and good luck!