Sorry, long story. Have sw2004 installed (WI method) & running OK, as far as I can tell. I wanted to put the last SP5.1 on sw2003, but it appeared to be InstShield only, and my sw03 was installed WI. So I uninstalled sw03 so that I could reinstall via InstShield. It refused to install in any way other than WI, and in the process of trying various things, now the install process has started a loop. Every time the machine boots, I get the message: "The Solidworks Service Pack Manager Wizard needs to reboot the computer in order to complete the initial installation of Windows Installer. Do you want to reboot the computer now?" It doesn't matter whether I answer yes or no. There's nothing in the registry under windows->current version->Run or RunOnce. Anyone know how to kill this? Thanks Bill