Language Keyboard keeps switching

Hi,
My daughter installed the Spanish keyboard through the Control Panel's
Regional Options/Input Languages.
Everything was fine for some time; she could switch from English to Spanish
without problems. But then the keyboard started switching unexpectedly
from one language to the other. So she removed the Spanish keyboard
service. All was fine until it started to switch back & forth to Spanish
again, even though the Spanish keyboard was not installed in the Regional
Options. Other than tell her to do a System Restore to a recent date, I
have no idea how to fix it. Is there a Key in the Registry that got
messed-up?
Appreciate any advice/help from the group.
Her computer: Dell notebook Inspiron 1150
Thanks
Roberto