I had this problem also, and just fixed it. What evidently happend was two files got deleted that prevented the start-up (/usr/lib/libpng12.so.0.1.2.2 and /usr/lib/libpng12.so.0 which was linked to the first file). So, here's what I had to do, and I'll go through step by step since I'm also fairly new to linux and it took me a little bit to figure it out.
1 - When you get to your grub boot loader, edit the boot process to change your run level to three (so, select your boot kernel, edit it, and add a '3' to the end of the line that starts with 'kernel', then press 'b' to boot off this new line since your changes won't persist)
2 - Now, you'll have a command line that you can work with. So, now find a buddy who has Fedora installed and get a copy of the /usr/lib/libpng12.so.0.1.2.2 file and copy onto your machine.
3 - Create a link to this file as libpng12.so.0.
4 - Reboot, and you should be good to go
I hope that helps you.