SimTresa That's good news at least. You can try playing in your main account now; sometimes that works once the game has been installed using a different one. If it doesn't though, my next question is what Windows has designated as the Documents directory in your main account. Your computer has several Documents folders, but only one per account is the directory, and Sims 3 tries to use this location too. If it can't write to that folder, the launcher can't open.
So if the game doesn't work in the new account, search in Windows for Command Prompt, open it, and enter this command:
reg query "HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders" /v "Personal"
This will return the location of Documents; please let me know what it says. You can write [username] instead of your actual username if you want, but leave the rest intact.