Uninstalling modules from DKMS
Attempting to install using DKMS

Creating symlink /var/lib/dkms/vboxguest/4.2.0/source ->
                 /usr/src/vboxguest-4.2.0

DKMS: add completed.
Error! Your kernel headers for kernel 3.5.0-23-generic cannot be found.
Please install the linux-headers-3.5.0-23-generic package,
or use the --kernelsourcedir option to tell DKMS where it's located
Failed to install using DKMS, attempting to install without
/tmp/vbox.0/Makefile.include.header:97: *** Error: unable to find the sources of your current Linux kernel. Specify KERN_DIR=<directory> and run Make again.  Stop.
Creating user for the Guest Additions.
Creating udev rule for the Guest Additions kernel module.