The computer is broken.
the computer has been broken or
the computer is spoilt.

Thank you.
The computer is not working.

"if it ain't broke, don't fix it" - taken the other way, we see that broken things can be repaired/fixed. Something that is spoilt ... is marred (eg has a stain) or beyond salvation (would you eat spoilt food?)

So the computer has broken down and can be repaired, but the CD may be spoilt if it is badly scratched up, over-written or something.