I have a question regarding game expansions.

Say there are 2 games: 'A' and 'B' and there is another game 'C' which is a stand alone expansion to the games 'A' and 'B'. It says in the description box of the game 'C' that if you have both the games 'A' and 'B' already installed then you can play the game 'C' with new and advanced features.

If I buy the game 'C' first without buying the games 'A' and 'B' and install and start playing the game 'C' and then after a few days buy the games 'A' and 'B' and install them, would I be able to play the game 'C' with those new and advanced features.............or do I have to first uninstall 'C' then install 'A' and 'B' and then reinstall 'C'?

For some reason I cannot edit the question and make corrections in my original post so I am re-posting the edited question here:

Say there are 2 games: 'A' and 'B' and there is another game 'C' which is a stand alone expansion to the games 'A' and 'B'. It says in the description box of the game 'C' that if you have the games 'A' and 'B' already installed then you can play the game 'C' with new and added features.

If I buy the game 'C' first without buying the games 'A' and 'B' and install and start playing the game 'C' and then after a few days buy the games 'A' and 'B' and install them, would I still be able to play the game 'C' with those new and added features.............or do I have to first uninstall 'C' then install 'A' and 'B' and then reinstall 'C'?

I think if you buy the stand-alone game "C", it will not really affect A and B. I had a similar case when I bought StarCraft: Legacy of the Void. That was stand-alone and I can still play the first 2 part of the games which the Sons of Liberty and Heart of the Swarm (2nd expansion) without buying them separately. So buying C will definitely include the contents of A and B if we're talking StarCraft here. I don't know in your case though. Btw, what is this game you're talking about?

You might as well tell us what games they are, i think this is a case by case basis.

Most game expansions require you to have the main game before you can play it. So even if you bought game “C” you wouldn’t be able to install or play it without game “A” for example.

Like the Dark Souls and Witcher 3 expansions. You might not even be able to buy them digitally on Steam without already having the main game like The Witcher 3 or Dark Souls 3 installed.

Most modern games wouldn't care about the order you installed them.

What games are you talking about?