Diagnosis
The drive motor or the gears that turn the barrel have failed. The whining is the motor trying to spin against a mechanical block.
How to Fix It
This is an internal repair. Unplug the unit. The issue is in the base, not the barrel. You can try a reset: unplug for 30 minutes, then plug into a different outlet. If the whining persists on power-up, the gearbox is jammed or stripped.
If That Didn't Work
The motor assembly is not user-serviceable. The plastic gears inside are known to wear or crack. You must contact Conair for a warranty replacement or purchase a new base unit.
Heads Up
Do not continue to operate it with the whining noise. It can overheat the motor and potentially cause a thermal fuse to blow, killing the unit entirely.