When i try to turn on the microwawe it flashes "door" and will not start. It appears to be sealing normaly

there is a motor under the underside of the microwave these motors can clog up. try turning the motor to by hand a few times so it makes a werring sound. if no sound its the slow gear in the motor broken and will need a new motor fitting.

Appears to need a replacement door switch, might just be cheaper to get a new microwave if it is old.
They are made to close tightly and sealed so you are not exposed to microwaves. Not sure how safe you are overriding the microwave safety feature standing nest to it holding door.

microwave repair YouTube

one or both of your heat cencors are bad or the mag there is a belt that turns the tray it must be wore out

see this causes and fix it. God bless you
Touchpad and Control Panel If the microwave buttons don't work the touchpad and control panel assembly are probably defective
Touchpad If the microwave buttons don't work the touchpad might be at fault. Generally speaking, if the display is working and some of the buttons respond correctly but some don't, the problem is with the touchpad.
User Control and Display Board If the microwave buttons don't work the main control board is most likely defective and will need to be replaced.

Main Control Board If the microwave buttons don't work the main control board is most likely defective and will need to be replaced.

see the video and proceed . God bless you

you got that quote from sharp?? You are under a defect warranty...they owe you a new one!!

are you saying the unit go's dead if thats the case there is internal protection shutting it down and some troubleshooting would be required to figure out what is causing it.

the latch is fixed without any screws...it is fitted with a sensor that makes sure that the microwawe stops wen the door is opened nd starts only if it is closed

This problem normaly happens when the door is not closed properly for a long time and flashing and buzzing starts to give user a indication for same. Allthough it is not risky as microwave oven has safty door switches wich does not allow oven to operate while door is open. Take care and close the door properly before you leave kitchen..