Spreadsheet Problems

I have a series of about 15,000 dates, all in the following format:

e.g. 91;3-24
Indicating March 24, 1991

I tried just doign the basic Format Cells, but to no avail. I would like to make some kind of Macro to do this for me so these can be plugged in as dates.
Anyone have any suggestions?


Also, on another spread sheet (probably because this was done on a 98 version of spreadsheet) when I copy and paste dates, the year, and day changes. Why?

Thanks