DIAGNOSIS No power is reaching the unit. This is almost always a connection issue, not a dead motor.
FIX First, check the obvious: is it plugged into a working outlet? Try a different outlet. Then, check the power cord where it enters the base—give it a gentle wiggle. If it feels loose, the internal solder joint might have broken. Also, make sure the cup is properly twisted onto the base. Many of these won't activate unless the cup is locked in place.
IF THAT DIDN'T WORK There's a thermal fuse inside the motor base that can blow if it overheats. If you've been pushing it hard with frozen stuff, this might have happened. That's not a user-serviceable fix; you'd need a new base unit.
HEADS UP Never submerge the motor base in water or run it under the faucet. If you need to clean it, wipe it with a damp cloth. Getting water inside will fry the electronics instantly.