** dryer heats up but will not dry clothes. [lots] of moisture in dryer **
That is usually the result of poor air flow through the dryer. I agree with MIGBOY that the most likely cause is a plugged, partially plugged or poorly installed (see the following link) dryer vent. It might also however be caused by a problem with the dryer's blower fan but is less likely IMO than the other and would usually create an added noise if it had failed.