Boot and Shutdown issues - Linux Mint 15 Olivia

Started seeing some hanging in system shutdown and issues booting up.

1. Removed modemmanager package
1. $ sudo apt-get --purge remove modemmanager
2. Enabled KVM support in bios
3. Returned to xserver-org-video-nouveau video drivers (had been using the recommended nvidia-310 set.

System now much more stable and shut downs and boots appear faster.