I found this. I know how to get into regedit but don't know what a Dword is. Could be a Dinah word for all I know.

To prevent MS Messenger from loading with OE you must do BOTH of these
things:
In Tools | Options uncheck the option to automatically logon to
Messenger.
AND
In View | Layout uncheck the Contacts Pane.
To just stop it from running follow this advice from Kelly:
"Only 3 Registry edits are required to stop Messenger and get rid of the
delay in OE. Start/Run/Regedit
HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Messenger\Client
Add the following values as New, DWord Values:
PreventRun
PreventAutoRun
Set the value of each of these to 1
Go to:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Outlook Express
Add a New, DWord value called Hide Messenger and set the value to 2.
(This step is required to prevent a long delay when opening OE with the
Contacts pane enabled)