Expansion codes are "invalid" on sims3.com

@zee122000  Is it possible that you registered Island Paradise on the Sims 3 Store site at some point, under a different account?  If so, then Origin would read the code as used (it shares information with the store) and wouldn't let you register it to your new account.  You could always contact EA customer support to ask what happened to your code.  Take a photo that has the disc as well as the back of the insert, with the code showing; you can provide it to the support rep during a live chat session.

https://help.ea.com/en/contact-us/

The reason that you could play with all of your packs on your old laptop was likely that you installed most of them via disc, including IP.  The Origin authentication process has changed over the years, and plenty of people used to be able to play with unregistered discs in an Origin-controlled install.  It doesn't tend to work now, at least not most of the time.  Still, if EA support can't help you, you could try installing IP via disc, after you download all the other packs from Origin.  This method will (probably) require you to insert the IP disc to play, but perhaps Origin will allow the disc to be your authentication.  Still, it would be better to get the situation sorted out with support, so you don't need to worry about it.

Thank you for responding!

So funny you mentioned using the IP disc to play! Even on my old laptop, if I didn't have the IP disc inserted, it wouldn't let me play the Sims at all! It would say "Please insert Sims 3 Island Paradise disc before continuing. And, the loading screen for the Sims is ALWAYS Island Paradise background! All of that just occurred to me. Is it possible that I installed it incorrectly all those years ago? It was one of the first expansion packs I had, and I never even paid any mind to it until now

I've always installed every expansion pack disc the same way, so its unlikely that IP is under a different account. Also, because I don't have another account.

I will attempt to install IP through the disk on my new laptop. I'm just a little worried that it will tell me that the code has already been used, and then im completely without the expansion. At the moment, I still have everything installed on my old laptop so everything is still playable and nothing has been touched, I wanted to make sure that I had everything in place before I transfer computers. I really don't want to lose everything!

I contacted EA live support a few days ago for an origin issue, they unfortunately weren't very much help.

Thank you for the feedback!

@zee122000  It sounds like you installed IP correctly the last time around, as well as the other packs.  The disc required and the loading screen you see both correspond to whichever pack is the newest by the date EA released it.  So if you didn't have Into the Future (or I think Movie Stuff), IP would be your newest.

If you install via disc, the disc itself authenticates your install.  If you download directly through Origin, then Origin authenticates.  That's why I suggested you try installing IP via disc, so you wouldn't need Origin to validate your ownership.  I honestly don't know if it would work, since this isn't something that typically happens.  And I'm really only guessing as to why your IP code wouldn't work when the others do.

Still, there's not a whole lot of risk in trying.  You don't need to uninstall TS3 on your old laptop before installing on your new one.  So if the new install doesn't work, you're right where you are now.  I still think it's worth contacting EA support though.  While troubleshooting is not always successful, the support reps are generally good at letting you know the status of your game codes.  If you provide the proof of ownership I described and ask directly for the information, you should at the very least get a solid answer.

Okay, I just looked because I was curious, and as it turns out, Sims 3 and all packs are on sale for $5 U.S. each on Steam right now.  You'd need to buy the base game through Steam as well, but that plus an extra copy of IP would still only be $10.  Then you could register your Steam codes in Origin, and they'd be available in your game library the same as your disc copies.  Plus if you've had your eye on any other packs, now is the time to buy.

https://store.steampowered.com/search/?term=sims+3