Anna, if you're getting these while surfing around on the net, just ignore them.
You can close them down by right-clicking your mouse and choosing the close option. (You can also close them down by clicking on the x in the top righthand corner of the box, but this is risky because some of these make it look like you're closing the thing down, but in reality you're clicking on something else. So safer just to use the mouse and then you're sure you're closing it.)
LabRat
