Missing worksheet tabs

I installed office 2007 on PC (XP) and laptop (Vista) last year. Recently I
did a clean install on the laptop and migrated some excel documents from the
PC to the laptop. When opened on the laptop, some (not all) of the excel
docs are missing the worksheet tabs across the bottom. I look back at the
same doc on the PC and all is fine.

A review of the excel docs on the PC shows two "types" present: Excel
97-2003 doc and Excel Worksheet. It is the latter that end up with the
missing sheet tabs after transferring to the laptop.

All of these sheets were generated sometime prior to installing Office 2007.
BTW, when I originally installed Office 2007, I did not run into this
problem. I have tried several varieties of "save as" but no success. I
also tried the microsoft support web site but was not able to find a
discussion of this problem.

Any help would be greatly appreciated.

Thanks,
Don