Brush Tool NOT drawing anything

** Look @ screen shots for reference **

I am really hoping to find an answer, because I've researched it extensively and cannot find a solution. 

1) The brush tool does not draw anything in the file 

- Sometimes, it works for a few minutes if I save my previous work as a JPEG and place the drawing into a new photoshop file. 

- One of my files could not draw anything BUT now I can't draw anything on a new file either 

---- The brush tool has become useless. I can't draw anything 

ATTEMPTS to SOLVE it 

- I've already went to Preferences, then Cursors and changed it into "Full Size Brush Tip" and "Show Cross Hairs in Brush Tip"

- I've opened and reopened my photoshop file 

- I've already reset my tools 

- My opacity is at 100%

- I don't have anything selected and if I did - I deselected it. 

Is the only solution to try to reset the entire photoshop applicaiton? And how do I do that?

Or should I undownload and redownload photoshop?

Thank you. I really want to finish some creative projects.