Trouvé avec Google :
1. Make the USB drive the first drive in the drive sequence. This is necessary because fdisk will not allow a partition to be active (bootable) unless it's the first drive. This can usually be accomplished by plugging the drive in, powering on the computer, and going into the BIOS to change the boot sequence. If this is unsuccessful, simply disabling or unplugging the other drives in your system (except the CD-ROM, of course!) will do the trick.
2. Boot the computer to a DOS shell from the bootable floppy or CD with the USB drive plugged in.
3. Run fdisk.
4. Set the primary partition on the USB drive to active by using "set active partition" (option 2) in fdisk. If you don't already have a primary partition on the USB drive, use fdisk to create one.
5. Exit fdisk.
6. Reboot the computer to a DOS shell from the bootable floppy or CD with the USB drive plugged in.
7. If you want, use the DOS command dir c: to verify the contents of the primary partition on the USB drive.
8. Format and copy the boot files to the primary partition using the DOS format /s c: command.
9. Run fdisk /mbr to write the master boot record to the USB drive without altering the partition table.
10. Restart the computer, this time booting from the USB drive. If everything went well, you should see the C:> command prompt.
Utilise un outils de traduction si tu n'es pas anglophone.