[root@computer user99672]# /etc/init.d/vboxdrv setup
Stopping VirtualBox kernel modules                         [  OK  ]
Uninstalling old VirtualBox DKMS kernel modules            [  OK  ]
Trying to register the VirtualBox kernel modules using DKMS
Error! Your kernel source for kernel 2.6.33.3-85.fc13.i686 cannot be found at
/lib/modules/2.6.33.3-85.fc13.i686/build or /lib/modules/2.6.33.3-85.fc13.i686/source.
                                                           [FAILED]
  (Failed, trying without DKMS)
Recompiling VirtualBox kernel modules                      [FAILED]
  (Look at /var/log/vbox-install.log to find out what went wrong)
[root@computer user99672]#