Yes.
It's a partial solution that works for most/basic tasks.
The subst command is not omnipresent.
Some low-level operations ignore the Subst mapping of paths to letters.
I thing he needs to pull this problem by the roots now, at the beggining.
Methaphorically, "Why stay with a mask if you can have the face?"

>
>I would not attempt to change the system drive letter as there is way too much in the registry that will be pointing to files by drive letter (including lots of Windows entries).
>
>You could work around it - put a 'Subst C: E:\' command in a .cmd file in your Start Menu\Programs\Startup folder and you should be fine specifying either E: or C: when you are logged in.