Painter not Painting

Weird, I've been using this program for a while now, but I open it up and whenever I start painting on a new, blank layer, the color never shows! Similarily, whenever I go to a layer with something on it, colour will only show on the parts I've already painted on.

Sorry to make a first post asking for help. =/
But I'd really apprecaite it..!

Hi welcome

the color you paint does not show on the transparent areas - but you can overpaint on areas already done?
make sure that preserve transparency is not ticked in the layers palette

Sweet.. Many thanks man!! =)

very useful feature when you want it - easily done by accident :)