I have a problem where when I try to paint using any type of brush or anything with brush in the tool name, I click and drag where I want it as normal and nothing appears on screen, yet if I go to "Edit" to undo it says "Undo Last Brush Stroke" so it knows that I have used a brush. Could you help? 

 Hi Jamlava.

There are two possibilities i can think of. 1- For some reason, or by pure accident, your default brush stroke color is white, and so you can't see the brush stroke against the white background. Check if this is the case. (or) 2. Your workspace has been corrupted. You can reset your workspace by holding down the F8 key while PhotoPAINT loads. Try this too.

Let's hope your problem has as simple a cause as the above.

 Thank-you very much, I can now carry on painting and editing!

 It worked then? Ah, that's nice. Carry on.