Cant access purchased music with new appl ID

I have similar if not the same problem! I had previously purchased songs with an apple ID that I no longer use. I changed my apple ID and now that i have a new macbook, anytime i try to play songs that i purchased with the old apple ID it will not allow my computer to play them. I try changing the apple ID to the new one and putting in the password and it just tells me that my system is already authorized. If i put in my current password with my old ID, it does not work. If i put in my old password with my old ID it also doesn't work. My old computer plays everything just fine which was the computer that i had when i changed my apple ID. I have went through step by step on the "iTunes repeatedly prompts to authorize content to play iTunes Store purchases" option on the support site and nothing has worked. Please help!

I am having the same problem. I used help advised by Apple to merge the two accounts, but now the songs try to use the old email address as an ID to authorise account, but the account doesn't exist. It doesn't recognise the new password or ID either. Has anybody managed to find a way to get these to work??

Every downloaded purchase has the account name embedded into it. You can see it by right-clicking and doing a Get Info. It's on the summary tab. This has a picture:
http://support.apple.com/kb/HT1920



You're going to have to forever remember the login credentials for both accounts. They won't "merge" 2 accounts - others have posted here asking for that, and I've never seen it happen.




If the old one isn't working, I think you need to contact iTS support. Use the Contact Us button at the bottom of this page
http://www.apple.com/support/itunes/store/email/



Maybe you just need to Sign Out between authorizing both accounts - have you tried that?
itunes menu > Store > Sign Out