Excel number formatting

I have two workstations that are running Windows 2000 and Excel 97. The number formatting is automatically using two decimal places and rounding; i.e. I key in 5 and it displays 1 showing .50 in the formula box. The format dialog box indicates that it is formatted for number, no decimals, minus sign in front of negatives. I have tried changing the formatting in the format dialog box, changing styles and uninstalling and reinstalling Excel. I have even posed this to a group of Microsoft Master trainers and still cannot figure it out.