You will need a usb dvd drive to plug into the acer (should be available for around $50 to $60 most places. My Acer netbook came with recovery discs if you have them you are good to go if not you will need a Windows OEM CD! And you will need to download the windows drivers from Acer! To boot from an attached USB drive, power the computer and press f12 when the logo shows on the screen this should allow you to select the dvd as the boot drive from there on just install Windows xp as normal!!