I tried the command, but it has not worked
I found that in /etc/fstab, the hda1 entry was preceded by a # and the mode was noauto
After deleting # and converting noauto by auto & rebooting, it's working fine
but...the floppy have the same problem, and the /etc/fstab entry is

/dev/fd0 /floppy vfat defaults,user,noauto,showexec,umask=022 0 0 (with no #)

is it the same problem ? 2 advice are better than 1

ThX