Data and gridlines disappearing in Excel 2007?

When working in Excel entire blocks of data and gridlines will occasionally disappear; sometimes one or the other, sometimes both. The data is in the cells, when I highlight the section, the data and lines reappear. I'm very proficient in excel, and have checked an color or formatting errors that may have occoured, and have not found a solution. This problem happens weather I'm using a file sent to me, or a blank one I create myself, so I'm relatively sure it is not a formatting problem. Has anyone come accross this problem, and found a fix?