A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
1
On your keyboard, if there is a Scroll Lock key (ScrLk), try pressing that key or Fn + that key to test if that resolves the problem.
2
If that was not the problem:
Open Excel.
Go to File - Options.
Select Advanced on the left.
In the 'Editing Options' section, enable this setting - 'Enable fill handle and cell drag and drop'
Save that setting and restart Excel.