extentofmysin

hi, ive tried to connect my pc with a wifi USB device which needs to access the internet by 'allowing other networks to connect through this computers internet connection' from the network control panel in, but- xp (SP2) keeps halting for ages... and then coming up with 'error 2: cannot enable shared access as cannot find the file (?) specified'. ive installed a new copy of xp. anyone have any idea on how it can find it, or what it is? Ive tried switching my firewall/antivirus off beforehand but its just the same. xp doesnt even state what file is missing. does anyone know how I can reinstall the internet sharing service?