Small Engines (Lawn Mowers, etc.): my weed eater stop cutting grass!!

Question
My troy bilt 2 stroke weed eater runs great. I was using it today and it all of a sudden stopped cutting the grass. So I payed closer attention to it an it was running at the right rpms, the head was spinning correctly, an it had string in it. I would like to know why it will not cut but it will run and spin the head just fine? Please help me.. I can't find any kind of answers or questions like this on the internet. HELP ME PLEASE!!

Answer
The clutch could be wore or the some part in the inner shaft could be broke.

I would take the shaft off and turn the inner shaft by hand to make sure the inner shaft is turning the head.  You can use a set of plyers to verify the inner shaft turns the cutting head.  Just hold the head between your feet and turn the inner shaft with the pliers...be careful not to damage (round off) the inner shaft when using the pliers.  When holding the head with your feet, if the inner shaft does not want to turn when using pliers then the inner shaft is good and you know the parts are working because you are preventing the head from turning with you feet.

Eric