I am trying to create a conditional formula where if a certain time period is
not met, the next cell to the right comes up 'Due'. To the right of the Due
column is a 'Sent' column for users to enter that a reminder email that their
task is overdue. When Sent is entered into the cell, I need the Due to be
removed.

Currently, I have;

IF(AND(G3<NOW(),I3="Sent"),"Due","")

where column G contains the time and date and column I is the Sent column.
If I remove the ,I3="Sent" section, 'Due' works but is not removed when Sent
is entered (obviously because I haven't told it too!) but when I include the
extra section, it doesn't work at all!

Please can someone advise?