This computer is already associated with an Apple ID

i have an apple id and my son has an apple id , he said he signed into his itunes through his windows user account and now i cant get my music or anything in my administator account !!!!!!!!!!!!!!!!!!! this is MY laptop computer so if you just must lock someone out of the apple music account that we pay for every month it IS WRONG TO GO lock the administrator out. NOW WHAT SHALL I DO ABOUT THAT , BESIDES WAIT THE REST OF THE 87 DAYS ??????

iTunes Store: Associating a device or computer to your Apple ID - http://support.apple.com/kb/HT4627 - In connection with, "When you turn on iTunes Match or Automatic Downloads, or when you download past purchases on an iOS device or computer, that device or computer becomes associated with your Apple ID." "Your Apple ID can have up to 10 devices and computers (combined) associated with it. Each computer must also be authorized using the same Apple ID. Once a device or computer is associated with your Apple ID, you cannot associate that device or computer with another Apple ID for 90 days." - Additional instructions for "Removing an associated device or computer from an Apple ID"

It isn't intended that you use multiple IDs to access accounts in different countries. In fact according to the terms of use of the store you are not supposed to use the store in another country unless you are actually resident in the other country (I imagine the number of people who can formally and legally claim residence in multiple countries is very, very tiny).

E.g., "The iTunes Service is available to you only in the United States, its territories, and possessions. You agree not to use or attempt to use the iTunes Service from outside these locations. Apple may use technologies to verify your compliance." - http://www.apple.com/legal/itunes/us/terms.html#SERVICE

Given that, if you used your other ID and are trying to redownload music or use Match you will have to wait the timed interval before reauthorizing the computer.

Yes, in fact I lived in Europe for 12 years. I even lived in a place 1 km from another country where people commuted daily to work in the other country. Still, residency was very strictly defined, and you could even get into trouble if you didn't re-register with the police when you changed address even inside the city. We bought food in the other country, went to restaurants there regularly, in fact the other country's train service stopped in our town and we had to pay for tickets in their currency (at the time). Still, residency was defined as a particular address in one country even if your paycheck came from a second country. We had an apartment in another country too but were told that for residency purposes we had to choose which one was going to be our country of residency, we couldn't be residents of both.

Even though Europe has reduced economic and work barriers there are still restrictions. I remember there were things you could buy in one country that were illegal in others. The age for drinking was different. It is possible media licensing laws differ from country to country. Yes, you can zip over to Spain and bring back a CD, but if you wanted to set up a CD store you would have to negotiate on a country by county basis not only with that country's business authorities (even though technically you have the right to set up a store you still have to deal with the red tape) but also also the media rights owners.

As I said, your problem is really due to you trying to use two Apple IDs with the computer to re-download or use Match (which is a kind of re-download). Apple does not say why this policy is in place but if you think it through you can see it might deter people from signing onto a friend's computer and downloading their purchases for their friend's use too, which is stealing. Very likely Apple has to work with the media providers about digital media policies or the media companies will refuse to allow distribution. Call your big, multinational media companies and complain to them.

Anyway, I did have the right answer in saying you would have to wait out the period.

***. My partner used my MacBook to download a show, watched it, logged out. We then deauthorized this computer from her account. Now I'm trying to download a show I paid for, and can't because of this. I paid for it, I want to download it and watch it now. Not 90 days from now. Come on, Apple, you're acting like Microsoft more and more. What happened to "it just works"???

Fix this!!!

IOS8.0.1