If you need to recover a CD from the drive there is a hole no bigger than a pin head on the front cover, typically near the volume control, insert something in there and this releases the drive door so you can pull it open and get your CD out.
Whilst the drive door is open turn your machine off and on - the system should autmatically close the drive door upon boot up - if it doesn't, as mentioned above the power is dead or the drive
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