re-enabling root and disabling plain user

[Erik Bågfors]

> Part (a) is going to be incredibly hard.  You may be able to do something
> evil and replace/symlink 'gksudo' to 'gksu', 

This is a default ubuntu:
: [bagfors at zyrgelkwytng]$ ; ls -l /usr/bin/gksudo
lrwxrwxrwx  1 root root 4 2005-04-05 09:39 /usr/bin/gksudo -> gksu*

: [bagfors at zyrgelkwytng]$ ; ls -l /usr/bin/gksu
-rwxr-xr-x  1 root root 18804 2005-04-04 23:08 /usr/bin/gksu*

gksudo is already a link. It operates in different ways depending on
how it's called.

/erik