I installed last week, now VirtualBox will not start a VM. It shows a dialog box:

Kernel driver not installed (rc=-1908)

The VirtualBox Linux kernel driver (vboxdrv) is either not loaded or there is a permission problem with /dev/vboxdrv. Please reinstall the kernel module by executing

'/etc/init.d/vboxdrv setup'

as root. If it is available in your distribution, you should install the DKMS package first. This package keeps track of Linux kernel changes and recompiles the vboxdrv kernel module if necessary.
Trying to do that:

# /etc/init.d/vboxdrv setup
bash: /etc/init.d/vboxdrv: No such file or directory
I do have DKMS:

# dpkg -l | grep dkms
ii  dkms                                                                            Dynamic Kernel Module Support Framework
ii  virtualbox-dkms                                                   4.1.12-dfsg-2ubuntu0.1                  x86 virtualization solution - kernel module sources for dkms
There is no /dev/vboxdrv on my system.

How to get VirtualBox working again?