Want to swich back to windows vista.

Question

I have recently bought my Acer Extensa 4420-5237 and i changed it to windows xp to get better use out of my memory and cpu. Problems occured with my wireless internet and have not yet fond a way to fix it and i want to go back to vista. But since it dosent come with a cd i dont know how to fix it, i was told that there was a way to make one off the computer.