weird EXCEL display

Not sure what happened in my EXCEL all of a sudden so I am posting this inquiry here.
If it's because my laptop is infected, well, at least I know which forum I should go next to seek help.

Below is the scenario.

I was doing a simple average and stdev calculation on two columns of numbers.
I copied and pasted the calculations from row2 to all the following rows in each respective column. What happened next is a mystery to me ??? While each cell displays the "correct" calculation formula, the numbers SHOWN are identical to the numbers in d2 and e2, NOT the calculated numbers. I need to click "Enter" on each cell to get the CORRECT calculation result. Any idea why this happened ALL OF A SUDDEN ?????


calculation
col1 col2 (ave) (std)
a 158 161 =average(b2,c2) =stdev.s(b2,c2)
b 125 172 =average(b3,c3) =stdev.s(b3,c3)
c 221 196 =average(b4,c4) =stdev.s(b4,c4)
.
.

shown
col1 col2 (ave) (std)
a 158 161 159.5 2.12
b 125 172 159.5 2.12
c 221 196 159.5 2.12
.
.

do you have manual calculation selected? (formulas tab/calculation options) try pressing f9...?

i've also seen calc updates fail when there is a circular reference in the workbook... even sometimes when the cell in question is not in any way a part of the circular reference (forumulas tab/error checking)

Thanks both. I closed the program and re-launched it and the problem is now gone ........ (and after re-launching, the automatic option was on )