It's not letting me get to ITunes and it's using my old AOL address and won't let me change it.

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So the new computer has to be authorized to play content purchased on iTunes.  You can authorize up to 5.  So first you'll need to find out the password to your old apple ID associated to the aol email address. It's very common for people to have more than one apple ID.  Apple also has a pretty easy method of reseting your password.  Remember this is not your email password.  This is your apple ID that happens to be associated with that email address.  After you've authorized that computer for that account then you need to log into iTunes store from within itunes with your current apple ID, which in your case may be your mobileme or gmail address.  

You can reset your apple password here.