While current electrical construction utilizes circuit breakers as safety devices for home wiring, many older houses may still rely on fuses to prevent overloads of electrical circuits. Replacing a fuse requires a bit more work than simply resetting a switch, but it's certainly a job that is well within the means of the average homeowner.
Inspect your fuse to ensure you've got the correct one. If you are using a glass fuse, look inside the fuse to see if the element is broken or burned through.
Unscrew the fuse from the fuse box by turning it to the left until the fuse pulls completely out of socket.
Insert a replacement fuse of the same rating into the socket and twist the fuse to the right to screw it into the socket.
Test the circuits which the fuse protects to ensure the power is back on.
If your fuse blows out frequently, consult an electrician to check your wiring for shorts or overloads.