F7 shows instead of door lock
This happens with a lot of ovens. It's because the mechanism that locks the door is stuck. When the door doesn't lock you can't do a self clean. They don't want you to be able to open the door while the oven is 800 degrees? or so. Look just below the little button that gets pushed in when the door is closed, upper left, and you should see a vertical slot. This is where a little lever comes out and grabs the slot on the door. There is a microswitch inside that tells the oven if the lever has come out or not. Your lever is stuck.
You can test this in a totally dangerous way by opening the door, holding in the button, and turning on the self cleaning. If everything is correct you will see the lever come out to grab and lock the door, but your's won't because it's stuck. Jiggle it or push on it or pull on it with needle nosed pliers. It frees up pretty easily. But when it does, the oven will go into self clean, which you don't want it to do with the door open, so turn it off, close the door and try again. It should work fine.