What command did you issue to upgrade with YUM?
Have you read the
fedorafaq?
Fedora uses udev and autofs to automount the filesystems on media (note, one does not mount
devices)
You should check the services, and make sure the autofs daemon is activated (or even present)
It could be as simple as missing entries in fstab, or a complex as needing to install/upgrade udev and autofs ... and/or making sure the kernel is compiled to enable these things.
KDE is irrelevent.