hello guys where to find game requirements like does this game work on windows 7

At least the Steam version works on Win7, it's just not supported. As for the rest:

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Until the Engine Update, I believe, Steam PSO2 should be able to work as far back as Windows XP using DirectX 9. Though don't count on it running well. I would know because I ran it on my old Media Center Edition PC back on JP's release in 2010.

Why you have a 14 years old OS?