import in australian dates

I use a programs that creates an excel spreadsheet from the data thats kept
in it, with the Australian date (dd/mm/yyyy) on the left. When I create the
spreadsheet excel mixes up all the rows (i think it pick some of them up as
dates some not). I need the rows to be in order. Is there any way to fix
this problem to make the rows appear in order? e.g. make excel not pick it up
as dates, or pick it up as australian dates?

Thanks