I just bought "The Sims 2 Pets", but when I tried to play it, it said that I needed to install "The Sims 2" first. I've never played any of the sim games on my computer, so do I need the original "The Sims 2" game to install on my computer first?

Yes. Pets is an expansion pack, not the core game. You need the original Sims 2 game first, then you can add expansion packs.

Yea, you have to buy one of Sims 2 or Sims 2: Double Deluxe. I think my manual says Sims 2 Holiday Edition will work too. you have to have one of these games to play with the pets, the pet one is an expansion. All of the other ones, if they arent listed above are expansion packs too. So, you can't play with just expansion packs, you have to have a base game.

Yeah you do... Sims Pets is an extension pack sooo that means that with it you can do more things in the game. Now, there's stuff packs too with allow you to have more objects in the game like the furniture, clothes, etc... So, yes, you do need Sims 2

Hope this helps! :)

Yes, anything other than The Sims 2 is an expansion pack and requires The Sims 2 base game to be installed in order to work. So basically, the foundation has to be made first.