I am preparing for an upgrade from IPCCx 4.x to 7.x and just received my CAD 7.5 cd from Cisco. I have manually uninstalled the 6.3 version of CAD on a test workstation including going through the manual uninstall documentation removing registry keys and whatnot. When I try to run the install for CAD 7.5 I get an error that says the operating system is not supported. My test workstation has XP SP3 on it. I searched the net for this error and found nothing. Could I really be the first to ever see this error?? Any ideas? Thanks!!