If you embed an Excel worksheet, or paste a picture of an Excel worksheet, the borders on the worksheet may not look right. This is usually because you are working in PowerPoint's Normal view, and the zoom is "zoomed out" so that you can't see all the detail on the slide. Before you panic that the borders have been destroyed, click the Slide Show button to view the slide full screen. Chances are good you'll see the borders are, in fact, still there.
There is an interesting quirk about Excel worksheets that are embedded (or linked) as Excel objects. Often, the gridlines will show on screen and when the object is printed. Simply turn off the gridlines using the View tab of the Options dialog box.

To turn off gridlines that appear in a linked or embedded Excel worksheet:

  1. Open the worksheet by double-clicking it.
  2. Choose Tools → Options.
  3. Click the View tab.
  4. Deselect Gridlines.