you seem to have the lts-vivid stack. so remove everything (virtualbox-* related) and install virtualbox-guest-dkms-lts-vivid.
I uploaded a new version on my ppa, will be available in an hour or two virtualbox-lts-vivid - 4.3.36-dfsg-1+deb8u1ubuntu1.14.04.1~14.04.4
you seem to have the lts-vivid stack. guest-dkms- lts-vivid.
so remove everything (virtualbox-* related)
and install virtualbox-
I uploaded a new version on my ppa, will be available in an hour or two lts-vivid - 4.3.36- dfsg-1+ deb8u1ubuntu1. 14.04.1~ 14.04.4
virtualbox-