Odd little box on my screen?

Not sure if this is the right forum but here goes, Sony Vaio VGN FZ260E, Vista Home Premium. There is an odd little translucent box on my desktop which stays on top of my windows. I have:confused seen it before but it is not always there and I can't get it to do anything or go away. Screen shot attached, does anyone know what this is? It is driving me nuts.

 

Does it start after visiting a particular website? Could you give us a full screen capture so it shows how it reacts with other open windows? For example a Desktop full screen capture with Windows Explorer open.

 

I never really noticed when it starts so I can't say if it's related to a website. Here are 2 more screen shots with open windows, it is harder to see with explorer open because it is white and translucent. Thanks for your input, I was afraid people would think I was nuts.

 

have you right clicked on it?
try disableing Aero, then reenableing(i recommened keeping it off on notebooks, unless you have a graphics card)

 

Yes I am running Aero and I tried right clicking which produced no result, I also tried dragging and left clicking. I have an NVIDIA GeForce 8400M GT graphics card. It's gone again this morning but the next time it appears I will try your suggestion. Thanks!