bug ubuntu

[armando . a]

dear gent 
may any body help me to get my computer back on order please 

i have problems with grub ,i try with recovery disk it doesdn   . 
last i  try to install grub in terminal 
came out this messaje below . can you recomended something 
even with cd live  i can no se the partion in the desktop , i tried
puppy caine other 

ill appreciate yoyr comments 

address@hidden:~$ grub-install -boot-directory=/boot//dev/sda
Unrecognized option `-boot-directory=/boot//dev/sda'
Usage: grub-install [OPTION] install_device
Install GRUB on your drive.

  -h, --help              print this message and exit
  -v, --version           print the version information and exit
  --root-directory=DIR    install GRUB images under the directory DIR
                          instead of the root directory
  --grub-shell=FILE       use FILE as the grub shell
  --no-floppy             do not probe any floppy drive
  --force-lba             force GRUB to use LBA mode even for a buggy
                          BIOS
  --recheck               probe a device map even if it already exists

INSTALL_DEVICE can be a GRUB device name or a system device filename.

grub-install copies GRUB images into the DIR/boot directory specfied by
--root-directory, and uses the grub shell to install grub into the boot
sector.

Report bugs to <address@hidden>.
address@hidden:~$