1) The socket it's plugged into may be defective
2) The fuse may have popped
3) You may have trimmed and cut the cable (unplug while you examine it for damage)
4) The trigger & interlock may be defective
5) There may be an internal wiring problem (doubtful)
6) The motor may have failed
1, 2 & 3 are the easy ones to check - 4, 5 & 6 will require more effort.
Peccavi
July 2013