wierd white box

[crazychicken]

i am running xp pro and office xp. when i close outlook, i get about a 2 inch by 2 inch white box with nothing in it that comes up in the bottom left hand corner of the screen. I have no idea what this is, and also, it partially goes away when i highlight items on the desktop.

it is very odd... does anyone have any ideas on what it is??

thanks
david