This can be caused by sawdust getting into the power switch, worn brushes in the motor, the motor worn badly and about to die completely, problems with the electronic motor control board or a bad connection between the plug and wall socket. It's also possible, but quite unlikely that a wire inside the power cord is broken, but this usually doesn't happen unless the cord gets bent sharply at the same exact place frequently for many, many times.
With the power cord unplugged from the wall I would first check the brushes. These are located behind small screw caps on the front and back of the motor. Be careful, because there is a spring between the brush and cap that will make the cap try to fly away if you aren't prepared when you unscrew it. Remove the cam and slide the brush and attached out of the hole. The black carbon part of the brush should never be shorter than about 3/8". If the brush wears away and the spring touches without the brush, the motor is history. Replace the brushes before they get too short and inspect them at least every 20-30 hours of running time.
Next I would remove the power switch. With care, you can carefully dis-assemble it and clean it, then re-assemble it. If you can't do this, at least try blowing compressed air through it. Then re-install it. A test run will see if this was the problem. I always wrap a layer or two of electrical tape around the sides of the switch to reduce the chance of saw dust getting inside. It still does, although it won't be necessary to clean it as often.
I would also check to see that the power plug is making good connection in the wall socket when it's plugged in..
Also check the fuse, fuse holder, and the fuse holder cap to be certain that all of the electrical connections are good and the fuse is also good. At this point it helps to have a multi meter and understand how to use it to make simple voltage and continuity measurements., but check the above and post the progress before trying to find and use the meter.