Comments disappearing, reappear, end up in different cells
 

Comments that have been made in a cell will randomly disappear, then come
back. Or they will appear in another cell, or be gone completely.
This problem happens to any workbook, or work sheet.
It's not a shared workbook.
Office has been repaired.
It's Excel 2003 in a 2003 Domain, Xp SP2 clients.
Excel might work for a day, or a few hours and then the problem will return.
I'm in desktop support for my company and it is only happening to 1 user,
and i particular pc.
Any help appreciated.
Thanks