If you can't download Bluestacks, first go to Start > Control Panel > Internet options > Connections > Lan. Make sure the system is not using a proxy because Bluestacks uses the system settings to make connections to the download server. Secondly, download the newly updated installer from its official website and make sure that before doing this you have the XP Service Pack 3 installed, because Bluestacks will not work with Service Pack 2. You can install the Service Pack 3 from the Windows Update.