I totally agree with "knowitall". You always start at the top and work down. Start with popcorn ceiling; finish and paint. Then paint walls. I would use carpet as drop cloth during all this. Roll up carpet, remove mess. Then install your hardwood floor. !!!Be sure you get your hardwood flooring in your home, preferably the room it's going in at least 2 weeks before you install it!!! Hardwood flooring needs at least 14 days on average to acclimate to your room's temperature and humidity, otherwise you will most likely get gaps or buckles shortly thereafter. Good luck!