All elements of a worksheet can be protected from accidental modification.
To protect a worksheet in Excel 2007 and higher versions, click the Review tab, click Protect Worksheet (or Protect Sheet), and click OK.
Excel 2003 and Earlier Versions click Tools > Protection, click Protect Sheet, and click OK.
Drag-and-drop is a mouse technique that we can use in Excel to pick up a cell selection and drop it into a new place on the worksheet. Although drag and drop is primarily a technique for moving cell entries around a worksheet, we can also adapt it to copy a cell selection.