Problema con formateo

Hello! Assistance after formatting the hard drive of my computer I would like to know how or where can I download the software that came already installed as default office, word. power point, excel, etc
another question also wanted to know if it is normal to try to format my computer out me an ad that says "it is possible that the computer inoperable" guess is that the windows are removed ..........
Now I would like to explain to me well before hand and appreciate any comment, Thanks .........
Greetings.
and forgive my English