Hi, format type thing really, see if you can understand me...

I've got some dates in cells (hundreds of them), and excel currently recognises them as text, eg. "12/02/99", not dates. However, if I select each one and press F2 followed by enter, excel then converts them to proper date formated cells, and they then appear in the formula bar in the format "12/02/1999". Now, I can spend a week or two press F2 on each and every bloody one of them, or someone could tell me how to automate this. I don't really understand why I need to do the F2 thing...