Squares in SharePoint

This year my company rolled out SharePoint 2010. A problem that has come up however is that for users with IE7 installed, sqaures appear in some text boxes on site new and edit forms. Don't beleive me? Check it out:

Normally this would happen if there is some text which the Operating System does not support, such as XP not being able to display chinese characters. These forms however are empty, after checking the HTML, there is no value set for any of these fields!