Hello, I’m Nathan, and I’ll be assisting you today. My livelihood depends on your positive feedback, so your satisfaction is my highest priority.
Sorry to hear you’re having trouble.
Unfortunately this is most often a hardware failure (bad motor, worn gear, loose belt, etc in the ejection mechanism, faulty switch or sensor, or just an obstruction by a disc that is out of place)
There are a few things you can try:
First unplug power for at least an hour, then press and hold the power/on button while plugging back in, and keep holding for another 60 seconds. If it still doesn't open, repeat the process but with the eject button instead of power.
If it still does not open, pick the unit up and shake/tilt the player side to side gently, hopefully dislodging the stuck disc inside that could be preventing it from opening, then try to open again.
If none of these help, then there is an internal hardware defect, which will need to be repaired.
If it gets to that point, I can advise you on service options. In general though, these units cannot be fixed (discontinued, no parts available), and are much more cost effective to replace than to repair.
You can't buy new ones anymore as it is a 15 year old model at this point, but you can get a used one still, if you wished: http://amzn.to/1OkF1Om
Overall, it may make more sense to digitize your collection at this point. It would take some time, but you can "rip" all your cds on your computer, then put all that music onto an ipod and play it all through your system that way.
I am an independent technician and I've spent my personal time, unpaid, in a good faith effort to assist with the question for which you solicited my services. I am only paid for my efforts when customers such as yourself leave positive feedback for my work. Again I apologize there is not a better outcome here, though this is really beyond either of our control. I do hope you’ll consider leaving a positive rating for me, rather than “shoot the messenger”, so that I may get credit for my time spent in good faith to answer your question accurately.