Ps4 Slim Nothing happens when I press power button

Hi.

I own a playstation slim 4, but have a problem that I can not fix & understand.
The thing is that when I press the start button, nothing happens to the playstation. Then when I press the button where you want to eject the CD, it beeps 3 times.

Do you know what the main problem is? What can I do to fix it?

I am a customer from Sweden. Thank you.