Office 2003 users cannot open files created in Office 2007
March 2, 2009If you are using SSL and forms based authentication Activesync will be broken
March 3, 2009Open registry editor.
Browse to HKEY_LOCAL_MACHINESOFTWAREWow6432NodeMicrosoftOffice12.0Registration
Under this there is a subkey that is a long GUID. Click on that and find the following keys.
DigitalProductID & ProductID
Delete them both.
Once these are deleted open any Office application and it will prompt you for a new key.