I am running the latest version of Ubuntu and I ran almost all the new updates. My screen and icons went blank since last upgrade. My Wifi is also not working. I have installed Gnome 3. The login screen also appears without any graphics. It's looking like classic theme. I tried to login to both default Ubuntu desktop and Gnome 3 desktop. But dint work well. I have installed it under Windows. How can I rollback the previous upgrades? Is there something like Windows restore point in Ubuntu?