If you find that you've accidentally created a HyperCard stack that closes
itself immediately upon opening -- and you can't edit it to correct the
problem, here's a way to force it to stay open.
In your home stack, make a button with this script:
on mouseUp
set lockmessages to true
go to stack "xyz"
end mouseUp
where "xyz" is the name of the problem stack. This will open the stack and
leave you at the first card.