Dvd will not open

Often there is an access hole through which a straightened paper clip can be gently pushed to work the ejection mechanism.
Unfortunately, in consumer products this hole is usually covered by the enclosure. You could try to remove the cover. There are no persistent dangerous voltages in this type of device once it is unplugged. However, even I, with a technical background, would not disassemble the unit unless I intended to scrap it and badly needed the disc. If you plan to have it repaired, let the technician extract the disc.