for me it was the problem of having the 586 kernel installed -- there's a bug in Anaconda which installed the wrong kernel
anyway, here's what I did, hopefully it will work for others
BACKUP GRUB.CONF! >> cp /boot/grub/grub.conf /boot/grub/grub.conf.old
rpm -e --nodeps kernel
rpm -e --nodeps kernel-devel
rpm -ivh http://redhat.secsup.org/fedora/core/6/i386/os/Fedora/RPMS/kernel-2.6.18-1.2798.fc6.i686.rpm
rpm -ivh http://redhat.secsup.org/fedora/core/6/i386/os/Fedora/RPMS/kernel-devel-2.6.18-1.2798.fc6.i686.rpm
cp /boot/grub/grub.conf.old /boot/grub/grub.conf
reboot and hopefully that helps
Dell Inspiron 9300 1.86GHZ Centrino, 1GB DDR2 533 dual channel, 80 GB Fujitsu PATA, Sony ATAPI DVD RW.
Dual Boot: Fedora 6 and Windows XP Professional SP2.
Built: 3 AMD computers all with ASUS motherboards, A8N-VM - socket 939 and M2N-E - AM2, P5B - 775 (Core 2 DUO).