formating and date changes
 

I am currently using excel2007 student version and each time i open my
spreadsheet it changes all the formating i've put in place. no currency and
the date is converted to the formula styl. ex: 39547. now i've noticed all
date entries have been adjusted to one forward. ex. 1-may-08 will now be
2-may-08.

does anyone know how to fix this?