Hello. My name is Michael. I will be your Primary Care Technician and I can assist you with your question.
Please look to the edges of the dvd tray to see if you can find a small hole - this small hole is the tray release override. It can be activated by putting a small object like a paperclip into the hole and pushing until the tray is released.
If you are unable to find a release override on your model (it will depend on the internal drive that was used in manufacture), there are some other things you can try - the most gentle of which is to open the unit and remove the top of the DVD player internally to access the disk and load mechanism.