This sounds like a blown thermal fuse or high limit thermostat. They will open when the dryer overheats. The most common cause of this is clogged or restricted ventilation. You'll need to check the thermostats and the thermal fuse for continuity and replace the one (or better, all of them) that has none. This is a lot more common than a switch; however, as part of your diagnosis, you'll also want to check the door switch for continuity.

Hey Thanks Magician ill check that out. but now after the dryer runs for a while and it finishes the cycle it wont start back up for another load.
could it be a bad switch?

makes this buzzing noise when you press the start button and continues to buzz while it's drying. works fine other than the noise.
Thanks David