Cursor is disappearing in the middle of my screen

[gaelan]

First noticed it in Firefox (newest version), but now in Mail and other apps my cursor seems to disappear in the middle of the screen. I mouse over to the perimeter of the screen and it reappears. From what I can tell there is a dead space? in the middle of my screen that measure about 5 inches in diameter.

Is there a setting to adjust? Do you think a 3rd party app is causing this?

 

[K3mp]

If you use arrows scroll down the cursor goes away and reappears when you move it.

 

[gaelan]

If you use arrows scroll down the cursor goes away and reappears when you move it.

i don't normally use the arrows to scroll