I'm replacing a ceiling light with a ceiling fan. I have 4 white wires I disconnected and a green wire- ground. There are 2 more white wires that weren't used, they are taped up. When I go to install the ceiling fan, it states use white, black and green. There are a total of 4 white wires from the ceiling. Any suggestions which one may be the black one?

If you have only white wires in the ceiling then something is seriously wrong.
Are there any other wires folded back in the box?
How was the fixture wired?
Can you post a picture of the ceiling box?

How was the light hooked up? Make sure the white wires are not painted over from spray paint when they did the ceiling.