The answer to 'how to fix a fuse box' is to first identify and replace any blown fuses. To do this, locate the fuse box, usually in the basement, garage, or utility room. Open the fuse box door and inspect each fuse. If a fuse is discolored or the metal strip inside is broken, that fuse needs to be replaced.
To replace a blown fuse, first turn off the circuit breaker for that fuse. Then, use a fuse puller tool to gently remove the old fuse and insert a new fuse of the same amperage. Turn the circuit breaker back on to restore power. If the new fuse immediately blows, there may be an underlying electrical issue that requires the help of a licensed electrician.