Have you checked to see if somehow those sheets have become hidden?  
Right-click the tab on the normal sheet and see if [Unhide] is available and
if it is, click it to see a list of hidden sheets.

My first suggestion would be to run the Office Diagnostics in Excel on the
laptop:
Office Button (in upper right corner)
[Excel Options] button that is then shown in lower-right corner.
[Resources] group from the left pane and then [Diagnose] in right pane.

That may show an immediate, detected problem and let you repair.  If it says
things are all fine and dandy, might try a repair installation of Office
anyhow on that system.

If none of that works, I'm thinking (just grabbing straws - nothing but thin
air to base this on) that perhaps the video card in the laptop is not up to
the job of displaying the graphics being output by the new Office (not just
Excel) graphics engine.  Many people have noted that graphic/charting display
is problematic in 2007 - most of the complaints being a slowdown of the
response of Excel when there are charts to be displayed, recalculated, etc.