Why do my Scroll bar go to row 500 when my data ends at row 50:

Excel may be remembering some data that was in row 500, but has been deleted. To go to the cell which is currently the "Last Cell" in the worksheet, hold the Ctrl key, and press the End key. If the Last Cell (cell J500 in this example) is outside the range of cells that is actually being used, you can reset the used range, so the scroll bar works correctly.
Note: If any cells contain references to the deleted cells, those references will be replaced with a #REF! error. If you have cells that are formatted, but outside the range that contains data, the formatting will be lost.
To manually reset the used range:
1. Select the last cell that contains data in the worksheet
2. To delete any unused rows:
 Move down one row from the last cell with data.
 Hold the Ctrl and Shift keys, and press the Down Arrow key
 Right-click in the selected cells, and, from the shortcut menu, choose Delete
 Select Entire Row, click OK.
3. To delete any unused columns:
 Move right one column from the last cell with data.
 Hold the Ctrl and Shift keys, and press the Right Arrow key
 Right-click in the selected cells, and, from the shortcut menu, choose Delete
 Select Entire Column, click OK.
4. Save the file. Note: In older versions of Excel, you may have to Save, then close and re-open the file before the used range is reset.