Fedora 17 black screen following plymouth

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http://forums.fedoraforum.org – Hi guyz, my laptop won't boot anymore, all goes well till i see the plymouth screen with the "drop" filling to the fedora logo. After that i get a black screen, gnome-shell doesn't seem to load. when I press ctrl-alt-backspace, I get the login screen with cursor but I can do nothing. The cursor moves but i can't click or type. I tried rebooting with the previous cursor but always the same problem. The problems started after I wanted to try the built-in grub theme by using the guide at this link. http://forums.fedoraforum.org/showthread.php?t=281792 I'm at windows no (HowTos)