Some cells within an excel worksheet don't appear
 

I am a new user to Microsoft Office 2007. I am working on a file that has
been extracted from MYOB and when I scroll up and down the screen information
on a row of data (not the whole row) doesn't appear.....there is information
in the cell however it is not visible. It seems to be when I scroll up and
down the screen rathering quickly when this occurs. The information is not
specific to a certain row. Sometimes the information will appear for a row
and then when I come back it will not be there and then it will be there next
time. If you highlight the entire area with the cursor the information will
then appear whilst on screen. It is very strange and I don't have a clue
what the issue is. In addition, I have highlight the whole worksheet and
made sure that the font colour is black however the issue is still occuring.
By the way if I adjust the column width the information will appear not just
for that row but the other row information that is missing too however when I
scroll away and come back it could be visible or it could not be visible.

Please help me....driving me crazy