how to authorize your computer for itunes

i just bought a new computer and sell my old one today, but itunes wouldnt let me re-download all the songs that i bought before. and i found out the problem was that i need to authorize my new computer first and if you have the same problem with me you can try this method:

if you have new itunes click on the box on upper left of the itunes screen then click > itunes store > authorize this computer you will then required to put your itunes email and passwords.

and if you have exceed the limited number of computer authorization for you itunes account you can go to > itunes stores > view accounts (required email and password) > then it will take you to different page and inside you apple id summary below your balance is the number of computer that is authorize to access to your account you can then deauthorize them all and dont forget to authorize your computer again. the computer and device (iphone, ipad, ipod, etc) are separated from computer authorization it is located right below it inside itunes in the cloud. one more thing you can only deauthorize all computer once a year so use it wisely.