For some users when they remove windows messenger or just disable it from starting up automatically they experience a great slow down when launching Outlook express. Users who experience such a slow down will find a error in the system error log saying The server {FB7199AB-79BF-11D2-8D94-0000F875C541} did not register with DCOM within the required timeout. The solution this problem is quite simple. Just Open up regedit and search for the string {FB7199AB-79BF-11D2-8D94-0000F875C541} and modify the keys InProcServer32 and LocalServer32 default key to a empty string. After a reboot, Outlook will start up as fast as possible.
Of course, to be on the safe side you should first export the keys to a safe location so you can reimport them if there are adverse results (not that there should be, but it can happen).