Why do I have no power in two rooms after plugging something in?
Check to make sure you didn't trip a GFIC breaker in one of the rooms. You will be familiar with these in bathrooms and kitchens -- the ones with the little Test/Reset buttons. They are often wired to protect a circuit in one or more entire rooms. Push Reset and see if your receptacles are now live.

If that doesn't work, try resetting each breaker by turning it off and then on.

If that doesn't work, look around to see if you have a subpanel set of electrical breakers lurking in a closet somewhere.

If there are no subpanels and the breakers aren't resetting your power, you may have a wiring failure and it is time to call an electrician.