Getting IE boxes

I'm getting an IE box when trying to type in names or passwords to sites, especially emails. I can't even access my email service at Rock.com. The boxes appear to come from a site I have visited but sometimes it may be from a site I visited the day before and not necessarily the last one I visited. There aren't any messages in the box (it covers 75% of screen) and usually only appears when I click in a username box but now it appears all of the time. I'm using XP if that helps. Is there a place where this can be turned off?

 

I'll try but all I think I can do is describe. Doesn't 75 % of the screen with the title internet explorer as a title with for example: Photobucket.com beneath it help?