Yes, press the ctrl and shift keys simultaneously. You should now see red outlines around the charts parts. Drag the legend box to the top or the bottom of the chart. When the red outline of the legend automatically expands to fill the entire width of the chart you can let go and the legend should be display horizontally.
Try like this
1) Chart Properties-> Click on Reset User Sizing and Reset User Docking buttons and click OK.
2) Now hold Ctrl & Shift keys simultaneously and drag the legend to bottom
Click ctrl+shift simultaneusly, you will see red containers appearing on the graph, drag the one with legends to the bottom until you see the black border for the legend.
Hope it helps.