Operating system is Windows XP. On opening e-mails first message is a Windows Installer message "Preparing to Install." The next windowd says "The feature you are trying to use is on a CD-ROM or other removable disk that is not available. Insert the Microsoft Office 2000 SR-1 disk and click OK". I do not have the disk. I do not use 2000 - I use OFfice 2003. Thanks for your time.