Windows 98 Error Message

Hello all. I have had a problem with one of our pcs that is running windows 98 and not sure what to do. No matter what she is working in she will get the following error message:

An error has occurred in your program. To keep working anyway, click ignore and save your work to a new file. To quit, click close. You will lose information you have entered since last save. Then when she clicks ignore it keeps coming up and when she clicks close she continues to get this error message causing her to have to reboot the system. This happenes about once a day.

Not sure what to do. Any help is greatly appreciated!!

Naseem