authorize itunes
iTunes says I can't authorize my computer to play music I purchase because I already of 5 devices authorized. I deleted one of the four my ID say's I have but ITunes still won't allow me to play music on this computer
You went to one of the computers that you had authorised and deauthorised it ? Or do you mean that you removed a computer or device from the 'manage devices' section of your account ? If the former have you tried logging out and back into the account on the computer that you want to authorise ; if the latter that has no impact on the number of computers that you have authorised.
Deauthorising : Deauthorize your computer using iTunes - Apple Support