Today my ubuntu 10 workstation has been acting strange. First when locking the screen, i come back and hit my usual spacebar to activate the login window, the mouse just flickers on and off. I have to restart gdm at this point. What then happened was the dual monitor setup got off. I opened the nvidia control panel and set it to the one where each monitor is seperate (forget the name). I didnt like that, so set to twin view which could never properly work. The monitors were getting odd display signals, and the refresh rate was bad. So i removed the nvidia driver and went back to using preferences > monitors. So the monitor setup is fine now, just the locking issue still occurs. The video card is an nvidia quattro of some sort. I later noticed that there were two screensaver applets. I removed screensaverx, then i couldnt lock at all. After that i reinstalled gdm and ubuntu-desktop. I can lock again, but the same problem occurs with the black screen and mouse flicker. I have to restart gdm to login.