Change display to spanish

Hello,
I just got this new laptop and I'm trying to change the language from english to spanish. This is my sister-in-law's laptop and she doesn't understand a word of english. I don't find a spanish option, I think I have to download and I need a reliable source and help to install. This laptop was just bought in the states and I'm down here in Honduras C.A....and just in case you're wondering...no, there was no military coup here...We will not let Chavez and his girls to take control of our country.