Computer not operating correct.

When I turn on my Toshiba laptop with window 7 the screen comes up with icons and wallpaper but then all the icons and start menu disappear. When I Ctrl, alt, del and try to do task manager it just does nothing. If I shut computer down I see some of the screensflash through and it says do you want to force programs that are open off then it shuts down, but I can not get anything to work.