You haven't provided much information. First, listen to the unit. Does the motor sound normal when you turn it on? If you hear it running and it sounds normal the motor is probably not "gone". If the motor is not running at all the machine will require a complete electrical checkout from the power cord, through the on/off switch and down to the thermal protector. According to your post you've checked the hepa filter - they are notorious for plugging up but I haven't seen one completely remove suction. Does the unit run but sound unusual? The motor protector by-pass valve (if equipped) may be blocked open (not normal - it tripped it should reset itself). The by-pass valve is circular and is located on the back of the unit - low and on the right. Good luck.
CHL, March 2006