screen resolution weird

[Rafnews]

Hi,

i installed an old laptop for my 3 years old son as in school they 
already learn how to do simple things with computer 9painting, watching 
cartoons, and so on...)
my problem is the following one:

After my son logs in F20 KDE, it's like all icons on the desktop are 
zoomed in.
when i move the mouse i can see that mouse pointer goes far far far 
below the bottom part of the monitor...so it's like the screen 
resolution is set up for people having problem seeing well....

even if i have the bottom bar with the icons and menus i can not reach 
it very well as mouse pointer must go "outside" monitor viewport to 
reach it and it is really bad thing.

If i log with my account, everything is ok, so i believe it's a simple 
issue but i must confess i don't know where can i check or reinit the 
gnome desktop to default (without losing son's game icons on desktop)

Any idea would be helpful.

thx.

A.