White line? help?

My game box that appears at the edge of the screen, I do not know what it is, someone has a solution?

https://dl.dropboxusercontent.com/u/62069766/fail.png

specs
Corei7, 16GB Ram, GTX690 Boost. (Win7x64)

EDIT:
I deleted all addons, But it continues.
Help please.

Do you have Avast? If so, restore anything steam-related from your virus chest. (Right-click the entry, click restore, and overwrite if it asks.) That’s what happened to me, and this solved my problem. If you don’t have Avast, I suppose you should try performing a similar function with your antivirus’s virus vault / quarantine / whatever it’s called.