I burned a cd from my itunes and it won't play on my stereo or cd player. Why??

Did you burn the CD as an audio CD?

If not, that's your problem. Otherwise, without more details I can only guess. You might try a different brand of disk, or if you're using CD-RW try CD-R.

Regards.

It's also wise to use a slower burn speed than the maximum supported - 50% or less for best results.