It looks like you use an nvidia driver for your video card. Could you try reinstalling the preferred driver using software-properties-gtk? Thanks!
2015-04-24 11:55:52,829 DEBUG Kernel uname: '3.17.4-031704-generic'
2015-04-24 11:55:52,836 DEBUG nvidiaUpdate()
2015-04-24 11:55:53,857 INFO no old nvidia driver installed, installing no new
It looks like you use an nvidia driver for your video card. Could you try reinstalling the preferred driver using software- properties- gtk? Thanks!
2015-04-24 11:55:52,829 DEBUG Kernel uname: '3.17.4- 031704- generic'
2015-04-24 11:55:52,836 DEBUG nvidiaUpdate()
2015-04-24 11:55:53,857 INFO no old nvidia driver installed, installing no new