Start Menu and Taskbar disappeared (opaque)

Seperate thread then the one below, my system literally has has gone blank on the bottom where the taskbar is and I can click on the start menu like its there and literally choose options even though it is blank. Could be the weirdest thing i have ever seen with vista. any thoughts. no porn or illegal on system, mcafee enterprise is running and shows no viruses. screen shot below




also please note that any type of windows screen the top of the screen where file, edit, etc is located is blank as well