formula not working when opened by another user
 

I have a large Excel worksheet with a number of formulars which are hidden &
protected - the idea being that users drop their new data onto the sheet the
formulars calculate & the result is displayed, without the user being able to
see or amend the formula. This works for all but one user (not sure of the
relevance but he uses a lap top rather than a desk top). Anyways when this
user tries to drop the data on to the sheet the formulars dont work & the
cells where its result should appear are blank - does anyone know what the
issue is?

I have checked their settings are set to automatic calculation. Also when
they use it sometimes they dont even get this far, the cells become locked &
therefore the protection kicks in & they are not allowed to paste the data
required.

Like I say this only occurrs for one user, no'one else - which suggests to
me it is a problem with their excel settings?