You've probably already thought of this, but:
if there is no light or any visible indicator still on, UNPLUG the
unit, wait a minute, plug back in.
If that don't work, UNPLUG the unit, turn it around, and look for a
"fuse". Little round door usually. Turn to unlock/open this, pull it
out, see if fuse is still in one length or has been burnt in two.
Replace with new fuse if burnt. Put old fuse back in if not.
Also: check to make sure wall plug is putting electricity out. Use the
lava lamp for this.