Microsoft Office Excel has encountered a problem

Hi,
I was working with Excel recording some research findings and suddenly a message popped up as shown below. It has now become a habit and whenever I open Excel a few minutes into using it, it just quits with the error message. Any suggestions?

Microsoft Office Excel has encountered a problem and needs to close. We are sorry for the inconvenience.
The information you were working on might be lost. Microsoft Office Excel can try to recover it for you.
Recover my work and restart Microsoft Office Excel
Please tell Microsoft about this problem.
We have created an error report that you can send to help us improve Microsoft Office Excel. We will treat this report as confidential and anonymous.
