Another way to inspect this is to simply rename the wabmig.exe in the \outlook express -folder, then run w2ksp51.exe, wait until the Welcome screen appears, then wait about 5 seconds more. A dialog is shown that says that the installer can not access the wabmig.exe. The installation is not allowed to continue. wabmig.exe is the address book import tool of Outlook Express, it looks for other email clients and when found imports the mail address list from them to be used by Outlook Express.