HELP! itunes...i need help!

Question

OK. New to this chat and much of the apple stuff so please be patient. I have been using different ipods and itunes for years. got a nano few years ago and built up a library on an hp laptop. i got a couple giftcards in november/december of 2008. i used some of them up and then didn't get on itunes for a long time. like months/year.
My wife got a macbook a few days ago. (awesome by the way) i plugged in my same nano. i logged in with an old email (which i haven't gotten emails to for over a year) and password. it worked and itunes asked my to verify billing info probably since it had been so long. i changed the debit card info to my current card and started to download songs.
first off i'm almost positive i had money left from previous giftcards. it never showed a balance anywhere?? i downloaded 23 songs and during a break i went into "account" to change to my current email and my current address. after doing so it took me back to this billing verification screen. i re-entered the CCV2 code from the back of my Visa debit card (it was the only empty field) and it said there was an error. i dod it again and same result.
so i then re-entered ALL billing info and got another error...this time telling me the credit card number i entered was invalid...? i quadruple checked, entered it 5+ times and always got the same error. "invalid credit card number" although I just made 23 purchases with the same info.
Anyway, questions i have are below...
1. Do gift cards expire?
2. Where is the remaining balance from previous gift cards?
3. is there anyway to look at past account history that far back to see what happened to gift card balance?
4. why is this happening with my credit card number after it worked fine?
5. my old HP laptop w? a bunch of songs crashed. i was able to save the songs. Can i put them on this computer's itunes?
sorry for having a ton of questions or if this isn't the right format or way to address them...first time on here. let me know. i despertley want to figure this out. thanks!

Answer 1

Hi and Welcome!!!
Once you go Mac, you never go back!
I have not been able to find anything about the gift cards expiring. Either online or on the ones I have (I'm sentimental, I save everything!).
You balance should appear, when you're in the itunes store, next to your account name/apple ID in the upper right--hand corner of the window. Remember, the iTunes application can have many users and the account balance will only be visible under the account under which it was redeemed (either your or your wife's).
To see your purchase history, select your account when you're in the iTunes store and log in. Once you get tot he account main page, click on "Purchase History." It'll list everything in chronological order from the most recent. You might need to access both accounts to get the full picture. Things purchased with gift cards will show up as "free."
The problem with your card might not be with your card. It could have been an online "busy signal." Or your card could be close to the limit or someone else could be using it. I'd call your bank to see what's going on. Hopefully, just some kind of internet misfire.
You can transfer your library to your new macbook by using an external drive of some kind. Just put them in the iTunes--iTunes Music folder on your home folder. The first time you try to play something on your macbook, it will ask you to "authorize the computer. You can also do that in advance by going to the "Store" heading near the "File" menu when you're in iTunes and selecting "Authorize This Computer."
Hope this helps! Good luck! And agin, Welcome to Mac and Apple Discussions! Come away from the dark side!
Sharon