Sims 3 error message 'remove the selected application' [ Edited ]

[SubparSpoonie]

I'm so confused,

I have The Sims 3, Plus: University Life and Generations and it installed without any problems.  But now I am trying to install Sims 3 Pets and when I put the disk it says "

Do you want to completely remove the selected application and all of its features? Yes or No.  I don't want any uninstalled, I want Sims 3 Pets to install.  It never even starts to install at all?  Why is this happening?  My PC meets all the requirements.  Am I installing it incorrectly? I can't find a thread that can help with this, I've tried so many things 

[Bluebellflora]

@SubparSpoonie

I've created a new thread with your issue as it wasn't relevant to the one you posted in

Please can you provide more information about your Mac. Instructions on how to do so here - http://answers.ea.com/t5/The-Sims-Mac/READ-FIRST-Sims-3-Mac-Help-Guides-and-Troubleshooting/m-p/4756...

[SubparSpoonie]

I'm really sorry to bother you one more, but I don't have a Mac, I have windows. Is there a thread you could redirect me to that could help me with this issue? Thanks  

[Bluebellflora]

@SubparSpoonie

I'm moving this thread to the tech. forum where a Windows user will be able to help you