I bought a fcm5dm freezer at a yard sale. Once I plugged it in and the compressor (finally) started running, I can not get the lid to open...on the front where the latch is it says (see warning on key) and the lid will NOT open. There is NO key but I do see where a slot for a round looking key might go. Also no manual with freezer just the sheet that is the technical data sheet. any suggestions?????????? thanks!!