The other night my brother pluged a sweeper in a receptical and now a ceiling light and some recepticals will not work. The breaker did not trip. There are other lights on that breaker that work fine just not the one light fixture and the recepticals that's tied into that breaker. I plugged a Tester in the outlet it reads hot ground reversed. Everything worked fine for years with no problems. Please help thanks!

Plugging in something with a hot ground reversal will usually trip the breaker. Make sure no breaker is tripped and pull the outlet to see why it is reading that way. Could be a crossed or shorted wires.

Is it a GFCI Receptacle? What room is it in? Kitchen or bath?

There is a loose wire connection someplace in the circuit.