strange Excel behavior

Hi,

I'd like to report a very strange behavior in Excel 2002. All excel sheets change a whole number to a 100th decimal place. For example, I typed 100 and hit enter then it showed 1.00, I even open new books and still problem persists. I checked the cell format and changed to all kinds of different settings but problem still persists. Every number is automatically divided by 100. I opened a saved workbook with lots of numbers in it. It looks fine until I reenter some numbers and hit enter, they appeared in 100th decimal numbers again. I can't go on like this. Any idea?

Tan Le