DIAGNOSIS: Complete power failure usually points to the internal fuse in the fan's power supply board, or a loose internal connection from the power cord input.
FIX: First, try a different electrical outlet that you know works, and use the fan's original power cord. If still dead, check the power cord itself for any kinks or damage. The next step is to check the fuse, but this requires opening the base. There's often a small, standard glass fuse (like a 5x20mm 250V fuse) inside the power module. If you're comfortable with a screwdriver and multimeter, you can open the base (voiding warranty), locate the fuse, and test it for continuity. A blown fuse is a common fail-safe for power surges.
IF THAT DIDN'T WORK: If the fuse is good, or replacing it doesn't bring the fan back, the AC-to-DC power supply board inside the fan has likely failed. This is not a user-serviceable part.
HEADS UP: This is a job where if you're not comfortable with basic electronics troubleshooting, your best bet is to contact Dreo support. They might send a replacement base unit under warranty if it's a known fault.