All electrical devices are connected in a complete electrical circuit. It only takes one poor connection or a break in the wire for the circuit to fail. Start as near to the power source as possible and then work systematically from the power source to the electrical item. Somewhere between the two there will be a loose connection or a damaged wire. If you use a multimeter to test for voltage, you can find out where the circuit fails and solve the wiring problem.
Turn off the main electricity switch on your fuse box. It's usually coloured red and is the only switch in the box.
Check the fuse box to find if a fuse has blown, or a switch has been tripped. Both can stop electricity from reaching your wall sockets. Reset the trip switch by sliding it to the "On" position, or check the fuses by pulling them out. You will be able to see if a fuse has blown since the wire will be broken. Replace the fuse and insert it in the fuse box. Turn on the main electricity switch. If the switch trips again, or a fuse blows, then you have a short circuit and will need to contact an electrician.
Turn on the multimeter. Put the jack plug on the end of the red multimeter wire into the "ACV" socket, meaning alternating current voltage, which is the type of electricity in your home. If the meter only has a "V" socket, then insert the plug into it. Insert the jack plug on the end of the black multimeter wire into the "COM" socket.
Set the voltage range using the multimeter dial. Your home electricity supply is between 110 and 120 volts, so set the dial to read up to about 130 volts.
Remove the plug from the wall socket that connects to the electrical device that's not operating. Put the metal sensors on the ends of the wires from the meter into the positive and negative connection holes on the wall socket. Slide the red sensor into the lower right hole and the black sensor into the lower left hole.
Read the multimeter display, which will be between 110 and 120 volts if there's an electrical supply. If the reading is near zero, contact an electrician to check your internal home wiring between the fuse box and the wall socket. If the reading is between 110 and 120 volts, then you know electricity is getting to the wall socket.
Don't reinsert the plug into the wall socket. Use a screwdriver and remove the plug cover. Check that the wires are connected to the plug terminals. If they're loose or not connected, reconnect them by inserting the wires into the terminal holes and tighten the screws. Looking directly inside the plug, the green wire connects to the top terminal; the white or grey wire connects to the lower left terminal and the black wire connects to the lower right terminal. Replace the fuse.
Replace the plug cover and tighten the screw so the cover is held in place. Insert the plug into the wall socket. Check if your electrical device operates. If it does you've solved the problem, if it doesn't, continue.
Remove the plug from the wall socket. Check along the wire from the plug to the electrical device to see if the wire appears damaged. If you find any damage or broken wires, replace the wiring between the power source and the electrical item. If there are no visible signs of damage on the wire, insert the plug into the wall socket and turn on the switch on the wall socket.
Look on the electrical device to find where the wires on the opposite end from the plug connect. Use the multimeter and put the sensors on the "+" and "-" terminals of the electrical item. The red sensor from the meter goes to the "+" terminal and the black sensor goes to the "-" terminal.
Read the multimeter display panel. The reading will be 110 to 120 volts if electricity is getting to the item. If there's not a reading, there's an internal problem in the wire, which will need to be replaced. If there is a reading, the problem is the electrical item, which an electrician can check.
Wear a pair of protective gloves to guard against touching a hot wire.