No. First, Outlook Express and Outlook are unrelated. You're asking the
same type of question as, "Can I delete WinZip after I have installed
Microsoft Flight Simulator?" The one has nothing to do with the other.
Second, Outlook Express is considered to be a Windows component. You can
make it inaccessible via Control Panel>Add or Remove Programs>Add/Remove
Windows Components, but why? Just don't use it.