Since the beginning of Microsoft Excel’s existence, it had a relatively minor, but annoying glitch: if you deleted cells all the way at the bottom or all the way to the right of a worksheet, Excel would still “remember” that those cells once had data. So when you press Ctrl + End to move the cursor to the end of the worksheet, the cursor wouldn’t go to what became the last-filled cell in the worksheet after you made your deletion; the cursor would go to the row and column of what used to be the last column and row of the worksheet.
To illustrate: in the sheet below, if you press Ctrl + End, the cursor will go to cell F11 (assuming no notation in G11):
What happens if you delete the data in rows D through F, and in rows 9 through 11, so the sheet looks like this (again, assuming no formatting or notation in rows 8 or 11)?
When pressing Ctrl + End, the cursor still goes to cell F11. To fix it, so the cursor goes to cell C8, instead:
Put the mouse pointer at the top of column D, so the pointer turns to a down arrow:
Drag to the right, so columns D through F are selected. Then right-click and select Delete from the pop-up menu.
Now do the same for the rows. Position the mouse pointer to the left of row 9, so the mouse pointer becomes a right arrow:
Drag downward, to select rows 9 through 11:
Again, right-click and select Delete from the pop-up menu.
Save the workbook. Now when you press Ctrl + End, the cursor will go to the correct cell: C8.
P.S. You can find free Visual Basic scripts that you can install that will fix this error, also. But using the method above, you don’t have to go through that.