We are running a web site on one of our web servers that requires login utilizing an Active Directory account in the same domain. This is also an SSL-encrypted site. The web server is IIS 5.x on Windows 2000 Server and the AD resides on its own box, a Windows 2000 Advanced Server. For some reason, all of a sudden XP machines cannot log on to the web site, but Win2K machines can. We have looked for a DoS attack in the logs, as well as any other intrusions, and we have attempted to reset the configuration on the server to no avail. We have also restarted both servers. We're sort of scratching our heads on this because we have no idea why it would occur out of the clear blue sky. If anyone has any ideas, please let us know.