Annoying green bar at the base of my desktop

[chrisb52]

I use windows 7 pro and recently it has developed a green horizontal bar (slightly more in depth than the tasbar) at the base of my windows logo desktop. It doesn't interfere with the taskbar which is in auto-hide mode, but how do I get rid of it?

 

[Cycloid Torus]

Could be hardware...does it change or is it constant?