Hi
I have first installed Win 7 without problem, (/dev/sda1)
After what, I install Fedora 12 (/dev/sda2 for /boot, /dev/sda3 for / and /dev/sda5 for the swap)
And then I install BT4 (/dev/sda6 for the swap, /dev/sda7 for /boot and /dev/sda8 for /)

After Fedora installation, I could go from one OS to another without problem.

But After BT4 installation, I could only go from Win 7 to BT4 OS, but I can not go under Fedora.
Is anyone familiar with grub?

Here is /boot/grub/menu.lst file

Code:
# menu.lst - See: grub(8), info grub, update-grub(8)
#            grub-install(8), grub-floppy(8),
#            grub-md5-crypt, /usr/share/doc/grub
#            and /usr/share/doc/grub-doc/.

## default num
# Set the default entry to the entry number NUM. Numbering starts from 0, and
# the entry number 0 is the default if the command is not used.
#
# You can specify 'saved' instead of a number. In this case, the default entry
# is the entry saved with the command 'savedefault'.
# WARNING: If you are using dmraid do not use 'savedefault' or your
# array will desync and will not let you boot your system.
default         0

## timeout sec
# Set a timeout, in SEC seconds, before automatically booting the default entry
# (normally the first entry defined).
timeout         10

## hiddenmenu
# Hides the menu by default (press ESC to see the menu)
#hiddenmenu

# Pretty colours
#color cyan/blue white/blue

## password ['--md5'] passwd
# If used in the first section of a menu file, disable all interactive editing
# control (menu entry editor and command-line)  and entries protected by the
# command 'lock'
# e.g. password topsecret
#      password --md5 $1$gLhU0/$aW78kHK1QfV3P2b2znUoe/
# password topsecret
"/boot/grub/menu.lst" 159 lines, 4614 characters           

# password topsecret

#
# examples
#
# title         Windows 95/98/NT/2000
# root          (hd0,0)
# makeactive
# chainloader   +1
#
# title         Linux
# root          (hd0,1)
# kernel        /vmlinuz root=/dev/hda2 ro
#

#
# Put static boot stanzas before and/or after AUTOMAGIC KERNEL LIST

### BEGIN AUTOMAGIC KERNELS LIST
## lines between the AUTOMAGIC KERNELS LIST markers will be modified
## by the debian update-grub script except for the default options below

## DO NOT UNCOMMENT THEM, Just edit them to your needs

## ## Start Default Options ##
## default kernel options
## default kernel options for automagic boot options
## If you want special options for specific kernels use kopt_x_y_z
## where x.y.z is kernel version. Minor versions can be omitted.
## e.g. kopt=root=/dev/hda1 ro
##      kopt_2_6_8=root=/dev/hdc1 ro
##      kopt_2_6_8_2_686=root=/dev/hdc2 ro
# kopt=root=UUID=7dd13e90-01b3-490f-9883-be5ca618659b ro
# kopt=root=UUID=7dd13e90-01b3-490f-9883-be5ca618659b ro

## default grub root device
## e.g. groot=(hd0,0)
# groot=3864bbd7-25ff-4a98-bd47-58307e1590f5

## should update-grub create alternative automagic boot options
## e.g. alternative=true
##      alternative=false
# alternative=true

## should update-grub lock alternative automagic boot options
## e.g. lockalternative=true
##      lockalternative=false
# lockalternative=false

## additional options to use with the default boot option, but not with the
## alternatives
## e.g. defoptions=vga=0x317 resume=/dev/hda5
# defoptions=vga=0x317

## should update-grub lock old automagic boot options
## e.g. lockold=false
##      lockold=true
# lockold=false

## Xen hypervisor options to use with the default Xen boot option
# xenhopt=

## Xen Linux kernel options to use with the default Xen boot option
# xenkopt=console=tty0

## altoption boot targets option
## multiple altoptions lines are allowed
## altoption boot targets option
## multiple altoptions lines are allowed
## e.g. altoptions=(extra menu suffix) extra boot options
##      altoptions=(recovery) single
# altoptions=(recovery mode) single

## controls how many kernels should be put into the menu.lst
## only counts the first occurence of a kernel, not the
## alternative kernel options
## e.g. howmany=all
##      howmany=7
# howmany=all

## should update-grub create memtest86 boot option
## e.g. memtest86=true
##      memtest86=false
# memtest86=true

## should update-grub adjust the value of the default booted system
## can be true or false
# updatedefaultentry=false

## should update-grub add savedefault to the default options
## can be true or false
# savedefault=false

## ## End Default Options ##

splashimage=3864bbd7-25ff-4a98-bd47-58307e1590f5/grub/splash.xpm.gz

title           Ubuntu 8.10, kernel 2.6.30.9
uuid            3864bbd7-25ff-4a98-bd47-58307e1590f5
kernel          /vmlinuz-2.6.30.9 root=UUID=7dd13e90-01b3-490f-9883-be5ca618659b ro quiet splash
initrd          /initrd.img-2.6.30.9
                                          kernel          /vmlinuz-2.6.30.9 root=UUID=7dd13e90-01b3-490f-9883-be5ca618659b ro quiet splash
initrd          /initrd.img-2.6.30.9
quiet

title           Ubuntu 8.10, kernel 2.6.30.9 (recovery mode)
uuid            3864bbd7-25ff-4a98-bd47-58307e1590f5
kernel          /vmlinuz-2.6.30.9 root=UUID=7dd13e90-01b3-490f-9883-be5ca618659b ro  single
initrd          /initrd.img-2.6.30.9

title           Ubuntu 8.10, memtest86+
uuid            3864bbd7-25ff-4a98-bd47-58307e1590f5
kernel          /memtest86+.bin
quiet

### END DEBIAN AUTOMAGIC KERNELS LIST

# This is a divider, added to separate the menu items below from the Debian
# ones.
title           Other operating systems:
root


# This entry automatically added by the Debian installer for a non-linux OS
# on /dev/sda1
title           Windows Vista/Longhorn (loader)
root            (hd0,0)
savedefault
makeactive
chainloader     +1
Thanks