Windows 7 wont install?

i have an acer aspire one it came with windows xp but i upgraded it to 7 so my harddrive had a failure so i bought another one and try to install 7 it wounldnt work.... i dnt knw what to do it wnt letme boot xp no more and windows 7 keeps giving me error message after it start expanding files)ijm booting from usb drive) i put linux ubuntu on it but i dnt like it .... i just wot windows back on my netbook please help