The glass globe won't budge , there is no screws . What do I do ?

If you are talking about a celing mounted flush mount fixture, there are no fitter screws around the metal base and no center post, try rotating the globe counter clockwise about a fourth of a turn. If it is stubborn, weare safety glasses and golves or cover your hands with a thick cloth before trying again.Expantion and contraction from the heating and cooling during use can cause the globe to seize. I bet it's a Hampton Bay.

Old Folks is right!. Almost all of the flush globe lights are a push up and try to spin the globe left, only a little bit.