Can't install any of the EPs or SPs

I have no idea how this installation goes wrong or anything. But I can install the base game just fine, it only has the registration code thing when I try to open The Sims 3 base game only. But I read that I could get rid of it, if I installed any of the EPs or SPs but I cant install any of them because it keeps giving me an 'error' that says I need to have the base game installed.
Just for other questions these are what I have already tried:
- Installed base game without patch and tried to install EPs/SPs = Keeps telling me to have base game installed
- Installed base game with patch and tried to install EPs/SPs = Keeps telling me to have base game installed

Everytime it just gives the error even tho I have the base game installed.

Hello I'm not sure what you mean by getting rid of the verification code? All the EPs/SPs and base game required code to be input before installing.

Firstly, have you read the guide on how to install the Sims 3 correctly on the forum? If you follow the guide + the one in the Ultimate Fix, the game should installed itself properly. 

Next, which torrent did you use? I advise the complete collection since all the installation are setup.exe files. I read that downloading each one separately, some have .iso files so that might be troublesome truth to be told. 

I advise to uninstall everything. If you have any mods/save files you can make a backup of them from the Documents folder. Be warned that when uninstalling the base game, the pc will auto delete the Sims 3 folder in your Documents (though i think there will be a notification before that). But since we're re-installing everything 'fresh', i advise you to back up first.

After uninstalling everything, EPs/SPs included (check to see if there are even though the it said can't install. Go to your Program Files and just delete the sims 3 folder if it's still there), you might want to clean your registry. Sometimes there might be a problem with re-installation.

Next, follow the guide here -> Installing Sims 3
Remember to download the Manual Patch and Ultimate Fix as well. Look inside the ultimate fix for the guide .pdf file. Follow the guide there as well. 

Hope it works for you.

I have downloaded the complete pack. And I re-installed base game with the guide, I downloaded the patch and then as I was going to install EPs/SPs it gives the error again.

Did you update the game with the manual patch before installing any EPs? Perhaps you could screenshot the exact error that appeared for clarification 

I did update with the manual patch before installing any EPs. ' To use this product you need The Sims 3 game. Install The Sims 3 before you install this product. '

Did the Sims 3 installed correctly? Did the error occur with other SPs/EPs as well? Also if you installed it to another location rather than the default C:/ it might give you that error.

How about cleaning the registry as I've mentioned and re-installing the base? It shouldn't which EPs you install first though. Also, double checking that your base game is indeed from here and not from other sites as that might not work. 

If you install it to another location -> Guide
Registration Code Fix ->here 
PS: I'm sure you've read them before but just checking to be sure.

I did get the error with other EPs/SPs as well. But I got it to work as I installed it on different location.

Thank you for your help.