paintbrush not working

[mindyt743513]

Hi, for some reason that if I click the paintbrush tool and click and drag anywhere it won't paint.  I have checked and none of the lay ers are locked.  I have attached a screenshot.  I have tried resetting the tools but that didn't help either.  other than closing and reopening Photoshop are there any other options?  

[barbara_a]

Is there a layer above the layer you are painting on that may have pixels that are hiding the pixels below it?