Still no solution Marco.. :-)
Look at my fstab file..I almost commented all entries..
/dev/hda3  /  reiserfs  defaults  0  1
#/dev/hda1  /agnula  ext3  defaults,auto  0  2
#/dev/hdb5  /data  vfat  auto,rw,users,defaults,umask=000  0  0

proc  /proc  proc  defaults  0  0
#/dev/fd0  /floppy  vfat  defaults,user,noauto,showexec,umask=022  0  0
#usbfs  /proc/bus/usb  usbfs  devmode=0666  0  0
sysfs  /sys  sysfs  defaults  0  0
tmpfs  /dev/shm  tmpfs defaults  0  0
#/dev/cdrom /cdrom  iso9660  defaults,ro,users,noexec,noauto  0  0
#/dev/cdrom1 /cdrom1  iso9660  defaults,ro,users,noexec,noauto  0  0
#/dev/dvd /dvd  iso9660  defaults,ro,users,noexec,noauto  0  0
# Added by KNOPPIX
#/dev/hda5 /mnt/hda5 auto noauto,users,exec 0 0
# Added by KNOPPIX
#/dev/hda6 none swap defaults 0 0

I did not commented neither proc nor sysfs because I thought those were important for the pc to boot correctly..Do you think I have to comment them to ?
And juste let /dev/hda3 ? And what if I comment /dev/hda3? The pc will not boot?
It is on that partition I have agnula..

So..as you see..after all these disabling..(and rebooting)..nothing works better..

For the other things you told me :

>  837 ?        00:00:00 ata/0
>  844 ?        00:00:00 scsi_eh_0
>  845 ?        00:00:00 scsi_eh_1
>   As instance, this process are not into my system. Maybe the problem is with
      scsi HDs, or SATA HDs.
>   Mmm.... what happens if you just kill them :P

I even tried as root..I can't manage to kill them..even with kill - 9.

A friend of mine told me that probably the ATA CONTROLLER is the one that shows the scsi interfaces..he says ATA interfaces are often shown as scsi interfaces..

> desc:   CMD Technology Inc|Silicon Image SiI 3112 SATARaid Controller
>     It's really a RAID system?

No, it is not a RAID system..it is a SATA controller...raid model..

Huh..I'm confused..although I know about softs..etc..in fact I'm a programmer Marco..so I'm generally ok with what you tell me...(hmm...you can speak to me as not a simple user..)..so..although I'm ok with soft..I know NOTHING abour hardware..
So..SATA..etc..I don't know what it is..
My friend told me..that the motherboard has the SATA controller shown above..
but I don't use it..

So..do you still think it could come from this? If we could in some way disable this controller? Or any new idea?

It seems that possibilities are decreasing..we have tried a lot of things ! :-)

Hope I don't make you crazy..or loose your time..

Julien.

When the system will work..I'll make a song for you :-)