Where can I find the right image for my PCs?

Hi!
I'm from Uruguay and I don't speak English very well.
I am the Technology Manager of the stake
In my stake we have 3 computer in the FHC. Two of them have windows 7 license and the other have windows XP licence, but all three have installed windows xp.
I do not know who installed them or if it was a request from the church.
Where can I find the right image for each computer?

Thank you

Sorry
Someone asked the same question as me.
My mistake was to ask before looking good

Thank you