wait so does that mean that i cannot have ANY of the music on my new laptop from the old account?????
Did I say anything close to that? I thought quite the opposite ("You can use items from other accounts on a computer").
As I said before, the occasion when people really run afoul of the authorization issue is when they get themselves in a position where they need to re-download (and I stress the "re"; yes, remember to see the "re" because we tell many people this and they never seem to get it) music from multiple accounts (say a drive failure) and they can't re-download from more than one account every 90 days. This does not apply to new purchases. If you always make sure you have a backup copy on another drive you never need re-download.
https://discussions.apple.com/thread/5833793?answerId=24659889022#24659889022
Apple IDs and iCloud - http://support.apple.com/kb/ht4895 - including multiple AppleIDs, and backup
Can I Put Multiple iTunes Accounts on My iPhone? - http://techtips.salon.com/can-put-multiple-itunes-accounts-iphone-3518.html
https://discussions.apple.com/thread/1965166?answerId=24882102022#24882102022 - I have purchases from my mothers Itunes account and fathers different Itunes account, so the music I would like to hear in my new itune library on a different MCBPro is split in two. So how can I authorise to [two] apple ids ?
Frequently asked questions about Apple ID - http://support.apple.com/kb/HE37
"I have multiple Apple IDs. Is there a way for me to merge them into a single Apple ID?
Apple IDs cannot be merged. You should use your preferred Apple ID from now on, but you can still access your purchased items such as music, movies, or software using your other Apple IDs."