When Messenger is removed using some of the popular uninstall methods, there is one registry key left behind that causes Outlook and Outlook Express to take a long time to load. On some computers, this may be accompanied by an entry in the error log saying "The server {FB7199AB-79BF-11D2-8D94-0000F875C541} did not register with DCOM within the required timeout"
To fix this, start REGEDIT.EXE and navigate to the key:
HKEY_CLASSES_ROOT\CLSID\{FB7199AB-79BF-11d2-8D94-0000F875C541}
You can also do a search for this key to get there easily.
In this key, you will find the keys InProc32 and LocalServer32. In both of these keys, there is a default key. Change the default key to a empty string. Reboot your computer after making the change.