I replaced it with a new desktop. I have iTunes and was able to restore my music library from my iPod. However, when I connect my iPhone (a 3G, non-jailbroken, most up to date apple software) it will not allow me to play any music from the iPhone nor store any newly purchased songs/albums to it. An error message told me that the iPhone can only be synced with one computer. Fine, I am not trying to join the Pirate Party or anything, I just want to be able to put the music I purchase on my device(s).
Is there a way to get my iPhone to accept new music from and play music on my new desktop?
I believe you have to change your settings in iTunes to allow for multiple computers. I haven’t done this personally so I wouldn’t know exactly how, but your other option is to email iTunes help and explain the situation so they can unlock your phone from the old laptop.
It sounds like you’re dismissing the dialog to reset the iPhone. You have to allow iTunes to erase the current applications and music on your iPhone to sync it with a new library.
Don’t do that; you’ll lose everything. Instead, mount your phone on the new machine, right-click on it in the “Devices” section of iTunes, and select “Transfer Purchases.” They’ll go into that machine’s library, and then you can synch the phone to that machine (you’ll have to authorize one of the songs against your iTunes account at some point in this process to authorize the computer).
This will only work for things purchased from the iTunes store: if you’ve got MP3s or something, you can just copy them manually from the old drive, or else you’ll have to re-rip them (or play around with third party software that can read unprotected files off the iPod/iPhone).
The OP already said he restored his music from his existing iPod, so his music will be fine. Additionally, any missing App Store apps can be redownloaded for free.