I run windows XP on a fairly new machine. I have four USB 1.1 ports. I want to buy an external HD, and therefore need to upgrade to USB 2.0. Is this process as simple as replacing the ports & attached PCI card with a new one? I have no room to add ports, I just want to upgrade. I already have a firewire port, but all the external HD's I have looked at require USB. Thanks!