Select the data that you wish to rotate. It can be a row, column or an entire table. Click inside of the first cell, hold the button and drag it until you've selected everything that you want to change.
Press "Ctrl" and "C" together to copy the data to your clipboard. Make sure that you see moving lines around the selection to ensure that it's highlighted and copied.
Click an empty XLS cell outside of the selection (the selection lines will keep moving to indicate that the information is still on your clipboard). Make sure that there is enough space around the empty cell to fit the block of data that you're rotating.
Click "Paste" in the drop-down menu on the "Home" toolbar. Select "Transpose" from the list of options to rotate the data. You can also choose "Paste Special" from the list of options, select the "Transpose" box and click "OK" to rotate the information in your worksheet.