My ceiling fan was working, I turned it off to replace the light bulb. I replaced the light bulb. The fan will not work now. It has never given us any trouble. I did flick the black switch that I assume reverses blade direction. I took the light bulb in and out. No difference. Light is working fan. Fan motor will not switch on. I live where it is hot, hot, hot. I need the fan to work. Any help?

Check Breaker, If 1 on pull chain, and 1 on switch, When installed, may accidentally been put on 2 different circuits.(Just check Breakers)
Verify fan direction not in middle. Pull speed control and check wall switch.
Worse case meter or tester will be needed.

Is it a remote fan? Does it have pullchains? See:

General ceiling fan troubleshooting and help FAQ- Ceiling Fans N More (http://www.ceiling-fans-n-more.com/ceiling-fan-general-troubleshooting-and-FAQ.php)