dryer will not start

First I checked for proper voltage at the electrical outlet.Then I lifted the lid to acess the hi limit.Found out that the hi limit was open keeping dryer from starting.The hi limit is a safety that prevents the dryer from overheating.Two things that come to mind that could cause this is a thermostat that is not opening and a plugged dryer vent.After removing the flex vent pipe I discovered that it was packed full of lint.The vent pipe runs up inside the wall to the roof and it was packed full.Had to vacuum it all out and climb onto the roof and remove and clean vent cap and screen.I replaced the flex vent pipe from dryer to wall,replaced hi limit and also it's a good idea to replace the thermostat as well.Not a hard job just takes a little time.Dryer workes as good as new.Total cost for parts $44.00