you need to re-install operating .
you need windows cd to install ,because you buy new hard drive nothing in there is be format,.
this you have windows cd or dvd, windows xp ,windows vista,windows 7.
please install is. and downloads drivers software install too went you finish install windows,webside what you have brand-name,like hp is will behttp://www8.hp.com/us/en/support-drivers.html
type your model laptop in then lick go