I am a financial analyst and I use Excel a lot.

Yesterday I lost the "drag" capability. By this I mean, if you are adding
two columns or more of data, you calculate the formula for one column and
then drag that formula to accompanying colums.

Starting yesterday, when I drag the formula from column a to column b, the
formula reads correctly with the column b addresses but it gives the answer
from column a that it was dragged from.
Same result for Copy.

You can audit the formula - it reads correctly data from column b, but still
gives the answer applicable to the cell it was dragged from.

This makes everything unreliable and uncheckable. Yikes!

I went to reinstall - repair - doesn't affect.

What happened?

Ditto for