So I refinished my oak hardwood floors about two weeks ago. Sanding process was not fun as I was taking off a mahogany stain that was really imbedded in the wood. I sanded with 36 to 60 to 80 to 120. Everything looked great. I did not put stain on and decided to go with a natural look. Then I buried myself when I put the polyurethane on. It turned out extremely gritty with tons of bubbles. It looks horrible. Then the other day I noticed it peeling and it was gooey underneath. I understand what I did wrong. Laid it on too think. Didn't clean good enough. Was rough with the poly before putting it down. But my question is this. Do I have to resand the entire floor bAck to bare wood? Or can I just sand it smooth and try re coat it?

I assume it's oil based poly. You should get it down to a smooth surface. Because of the gooey situation you'll probably be removing quite a bit to get it smooth. If you leave any areas of poly you may have a problem trying to feather them smooth and the ridges will be visible....you may get a smooth level surface but you may see any ridges that you have left Real thin coats....lightly scuff between coats to prevent creep.

Let the coating cure some before you start to work on it. It should be hard all the way through before you try to smooth the defects. You may need two thin coats to make it look right after you sand to make it smooth. Feather the worst spots with a random orbit hand sander with 100 then 120 before you try another coat.

Be careful with the sanding dust! It can spontaneously combust if kept in a confined container. Spread it out or soak it in water as soon as it is sanded.