"No bootable device" error when I start my Mac mini?

My Mac Mini (2012, i7, 16GB Ram) is not working.

I tried to install Windows and by accident I made the installer restart. Now my computer gives this warning each time I turn it on.

Also, every time I turn the Mac on, I don't hear the 'duhhhhhhhh' chime.

I know this Mac is old but I seriously need this to work again!!!!

I have also tried going into recovery and the boot menu but no success, The system is basically locked.

Do I need to replace internal components??

Any help is appreciated.

[Re-titled by Moderator]