Or in VI, just do:
:%s/^V<Enter>//
that is, :s/ then Ctrl-V to accept a control
character, then the Enter key, and then two slashes.
This will remove all CR characters
throughout the file.
Obviously a command line is superior,
but this is good at the moment when you
VI a file and just want those ^Ms to go away.
I'm sure an equivalent is handy in Emacs.
(I also go to Emacs when VI chokes on
overlength lines. Otherwise I stick with
VI largely because of its ubiquity.)
Vic