Check out the info here, it should help:
http://support.microsoft.com/kb/197555/en-us
"KMV" wrote in message
...
I selected the wrong religious group when adding holidays and now I can't
remove them all at once. Help says remove each one manually. When I go
back
into Calendar options, Add Holidays, the only box shown as checked is
United
States holidays even though others are displayed on my calendar. I
thought
I'd be able to 'uncheck' a country/religious group and remove all holidays
for that group.