I cannot open CD device

First thing to do is try to reset your stereo system back to factory settings. I downloaded a copy of the owner's manual to the device page here.

W0002349M Micro HiFi Component System Operating Instructions - iFixit

Here's the section on Resetting the System:

1. Disconnect the power cord from the wall outlet.
2. Press I/0 down and connect the power cord to the wall outlet again.

The system is reset to the factory settings. All previous settings such as the preset stations, clock, and timers are cleared and must be set again.

If that doesn't help, you can try manually ejecting the disc; although I can't tell you exactly how, most CD players have a tiny hole, generally in the disc tray or very close to it, where you can stick a straightened paper clip in that will activate the manual eject mechanism and allow you to open the tray by hand.