Hi
In fact I have found that solution
"C:\pathToXL2007\excel.exe" /regserver
but on my machine
- it works perfectly with the Excel.exe of 2003 version
- but not with the excel.exe of 2007

in the first case HKEY_CLASSES_ROOT\Excel.Application\CurVer move from
Excel.Application.12 to Excel.Application.A11 = perfect... Excel is not
opened, just some small installation windows...

Unfortunately - In the second case excel open and nothing hapen regarding
the default excel which stay to Excel.Application.11

Any idea ?
Thanks and Regards
Alain