If you cannot find the serial number, or you have deleted the email, you can find your code in your Order History by going to Origin > EA Account and Billing... > Order History or directly by clicking My Account.
Before you make yet another post about invalid serial codes, read thisInstructions on how to register the game can be found here: How to Register The Sims 3 and also read the following [FAQ] Invalid and Used Serial Codes & Games not showing up in Origin
If you bought through Origin, there's no need to register again. Go to your myPage on thesims3.com and check if your icon shows up. If it does, you're good to go. It may take a moment to show up, so don't despair. I'm unsure at this point what happens if you never had an account before or if your accounts on thesims3.com and Origin do not have the same email address.If it isn't, it could still be the matter of broken icons, so try to redeem your limited and Origin codes to get the bonus content, if you can, your game is registered fine. You do not need to do anything else.If you get an error message on the redeem page, go check your purchase history to see if it's availble to download anyways. If it is, all is good.If it doesn't you need to contact Customer Support. Don't choose the AnswerHQ option, you'll be redirected back here. Live Chat is the only option!! No one here will be able to help you with invalid codes. We're users like you.
If you still have the game on your computer you can follow these steps to find your serial code from your registry (PC only). Credits of to Carl's Sims 3 GuideYou need to be signed in as an Administrator first. Windows may require your permission to open theRegistry Editor and if so, just click on yes.Press the Windows key on your keyboard and type regedit in the search bar and press Enter. Click on 'File' at the top left of the window that opens then click on Export.Choose a location and name for the file as this will be your backup registry file.Click Save.This backup is created just as a precaution.Now to find your serial codes for each specific EP or SP installed on your computer:Expand the HKEY_LOCAL_MACHINE folder.Expand the SOFTWARE folder (Wow6432Node for 64 bit systems)Expand the Electronic Arts folder.Expand the Sims folderExpand the EP or SP you need the code forClick on ergc and in the box to the right under 'Data' you will see the codeWrite it down somewhere safeRepeat above steps for each EP---------------------Otherwise, you will need to contact a game advisor: . For help with navigating the site, see this: -Archive/How-to-contact-a-Game-Advisor-using-the-new-EA-Help-page/m-p/2...For more information: -Sims-3/FAQ-Lost-and-broken-DVDs-and-missing-serial-codes-What-to-do/td-...Best of luck and happy gaming 2b1af7f3a8