After the installation of Red Hat 7 my system (a HP Omnibook 4150 notebook) does not boot linux but hangs after the "enabling Swap" sequence. You can make it work, when you remove the line "modprobe agpgart" from the file /etc/rc.d/rc.sysinit. If you give the command "modprobe agpgart" during runtime, the system hangs immediately and does not react on anything anymore. You need to turn the laptop off and on again.
*** This bug has been marked as a duplicate of 18793 ***