Did/does it look like this?

If so, to get rid of it click inside the lens area, it should go away.
Couple of things now: To prevent that from showing up again (unless wanted), go to your Preferences and click this option:

Lastly, the magnifying glass only comes up in the Preview Panel. BUT you cannot select or move an image from the Preview Panel, only the Content Panel.
FWIW, the default Panel layout in Bridge is not very good. If I want to look at Previews, I was to SEE the Previews so I move the Preview Panel all by itself to the middle collumb in Bridge. If you grab (wiht the mouse) on the Tab name, you can move it anywhere in the Bridge window. I move it to the middle, all by its lonesome. Generally I have the Content Panel by itself on the right side (also by itself). Any other Panels I want to see are in two rows on the left side.
Let me know if this solves your problem.