Diagnosis
Complete power failure points to a tripped thermal fuse (common in compact appliances) or a faulty power supply/internal wiring. Check the simplest things first.
How to Fix It
First, verify your outlet works by plugging in another device. Second, check the power cord for any visible damage. Third, and most likely, the unit has an internal thermal overload protector that needs reset. Unplug it, wait 30 minutes for it to cool completely, then plug it back in. This often resolves it.
If That Didn't Work
If a full cool-down reset does nothing, the thermal fuse on the compressor or control board may have blown permanently. This typically happens from prolonged overuse or poor ventilation. This requires professional repair or component replacement.
Heads Up
These units need several inches of clearance on all sides, especially the back, for airflow. Operating it crammed in a corner against a wall is a surefire way to overheat it and trip the thermal cutoff.