Why won't any light in my house turn on after a range hood was installed?
Definitely sounds like either breakers/fuses/main power were left turned off, or he did something that caused breakers to trip or fuses to blow, or he damaged the wiring in some other way. 

Breaker/fuse box is the first thing to check.

If that isn't it... he touched it last, he didn't get you to confirm that everything was working properly before he left, he owns the problem.

(Though if you've got other work going on it may not be the electrician's fault. After some work was done on my place, one specific bathroom's light failed to turn on. Electrician swore he hadn't done anything to that circuit. He was right; one of the carpenters had hit the cable with a sawzall. I had to find that break myself. I must say they were good about fixing it once I pointed it out to them, and the carpenter apologized profusely for not having checked for wires before he started cutting.)