One way:

Select the cells where information CAN be entered. CHoose
Format/Cells/Protection and uncheck the Locked checkbox.

Choose Tools/Protection/Protect Sheet... (password optional).


In article ,
Bryan wrote:

I have created a spreadsheet that has columns that automatically totals test
scores. I have noticed that on more that one occasion I accidentally entered
an amount in the totals column which screwed up my calculation. How do I
prevent myself from accidentally entering data in a totals column?