So, after a good 15 years of photoshopping, I can not make a NEW doc with transparant background.
I hate you soo much, and this new start and new "splash" is ugly too.
Check Preferences and see if you have the Transparency Grid set to None
[EDIT] We cross posted there Dave, but it is 4AM here, and my own settings are not at optimum. :-( It has been damn hot here, and I made the mistake of drinking a second cup of tea after midnight. Time to try again...