What would cause the data to become invisible in an excel worksheet or a word document?

I have my check registser in excell and just used it yesterday to deduct what I spent, today when I click to open the worshsheet to deduct a purchase today. It opens and there is no data visible. When I check properties on the file it has 364 KB. If I open a new excell worksheet to start a new one it goes into not responding and can't even start a new worsheet.