I suggested recompiling kernel as 'kernel panic' messages are
often associated with not selecting the correct processor in the kernel. However other things can also lead to this error message. It may be because you are using a usb drive to boot. Can you boot into Fedora using the hard drive or do you get this message? If you get this message you may need to change the processor setting in the kernel or you can do it to optimise it.
Download instructions from the internet for Fedora. They are also included in the kernel tar file, which you can read if you
use tar or bunzip2 to unzip it. Back up everything first though so it can be restored if you stuff up - which unfortunately is not uncommon. ONLY modify processor selection at first. Running at 64 bits for an Athlon processor should not be a problem. Most linux distros change the menu selection for you and don't wipe your windows partition unless you tell them to do so when you
install linux. Windows on the other hand doesn't like linux and can happily trash everything if you reinstall it. You compile the kernel using Fedora on your internal hard drive. There are too many steps involved and some distros have a twist on it, hence download instructions from internet for Fedora.