I have just installed Debian 5.0 amd64 from a net install CD. Several other operating systems exist on my hard drive. When I boot Debian it looks for (hd1,7) as the root partition so I edit that line to (hd0,7) and it starts to boot as expected and then halts after about 2 minutes with the following message

Gave up waiting for the root device. Common problems:
-Boot args (cat /proc/cmdline)
-Check root= (did the system wait for the right device?)
-Missing modules (cat /proc/modules; ls/dev)
Alert! /dev/sdf8 does not exist. Droping to a shell!

I have had Debian installed before with out this problem. Any help would be appreciated.

type fdisk -l post it and point out what OS is ON what system. the problem you have is your grub does not match the fstab file of your root file system or you pointed it to the wrong system on the wrong partition.

This is fdisk -l below

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00038487

Device Boot Start End Blocks Id System
/dev/sda1 1 7833 62918541 83 Linux
/dev/sda2 7834 26109 146801970 83 Linux
/dev/sda3 * 26110 32636 52428127+ 7 HPFS/NTFS
/dev/sda4 32637 60801 226235362+ 5 Extended
/dev/sda5 32637 39163 52428096 7 HPFS/NTFS
/dev/sda6 39164 40207 8385898+ 82 Linux swap / Solaris
/dev/sda7 40208 46734 52428096 83 Linux
/dev/sda8 46735 53261 52428096 83 Linux
/dev/sda9 53262 60801 60565018+ 83 L

This is whats on each partition

/dev/sda1=/ ubuntu primary
/dev/sda2=/home ubuntu primary
/dev/sda3=Winxp primary
/dev/sda4=extended partition
/dev/sda5=Win7rc logical
/dev/sda6=Swap partition (don't know why it says /Solaris) logical
/dev/sda7=OpenSuse 11 logical
/dev/sda8=Debian 5.0 amd64 logical
/dev/sda9=nothing on that partition logical

In my first post I said that I corrected grub to (hd0,7) so it should boot. No

Update I got Debian to boot by editing 2 lines in the grub screen.
Now it boots but hangs with a graphic card problem (no message)
Any thoughts?

What graphics card are you using? Can you type commands in at the terminal? You could post your xorg.conf file (from "cat /etc/X11/xorg.conf") and/or the results of "tail /var/log/Xorg.0.log" or "cat /var/log/Xorg.0.log | grep EE".

EDIT:
...all the above commands should be typed without the quotes.

If it stops loading with the graphical and stops this tell me it has found the kernel it has found the intrid.img but the uuid is incorect for that drive. this is on the fstab.

if you pres the esc key a couple of times you will see it hung up with just a flashing prompt. Debian assigns a uuid per harddrive.
another way to try and solve this is to edit your /grub/menu.1st with this.

title linux sda8
root (hd0,7)
configfile /boot/grub/menu.1st

Now when you boot into grub you choose linux sda8 it will go to the /dev/sda8 or in grub language (hd0,7) and load that menu.1st file now you are actually using the file written by debian for that drive. good luck

Output of first code below

# xorg.conf (X.Org X Window System server configuration file)
#
# This file was generated by dexconf, the Debian X Configuration tool, using
# values from the debconf database.
#
# Edit this file with caution, and see the xorg.conf manual page.
# (Type "man xorg.conf" at the shell prompt.)
#
# This file is automatically updated on xserver-xorg package upgrades *only*
# if it has not been modified since the last upgrade of the xserver-xorg
# package.
#
# If you have edited this file but would like it to be automatically updated
# again, run the following command:
# sudo dpkg-reconfigure -phigh xserver-xorg

Section "InputDevice"
Identifier "Generic Keyboard"
Driver "kbd"
Option "XkbRules" "xorg"
Option "XkbModel" "pc104"
Option "XkbLayout" "us"
EndSection

Section "InputDevice"
Identifier "Configured Mouse"
Driver "mouse"
EndSection

Section "Device"
Identifier "Configured Video Device"
EndSection

Section "Monitor"
Identifier "Configured Monitor"
EndSection

Section "Screen"
Identifier "Default Screen"
Monitor "Configured Monitor"
EndSection

Output of second code below

(**) Option "XkbLayout" "us"
(**) Generic Keyboard: XkbLayout: "us"
(**) Option "CustomKeycodes" "off"
(**) Generic Keyboard: CustomKeycodes disabled
(II) evaluating device (Configured Mouse)
(II) XINPUT: Adding extended input device "Configured Mouse" (type: MOUSE)
(II) evaluating device (Generic Keyboard)
(II) XINPUT: Adding extended input device "Generic Keyboard" (type: KEYBOARD)
(--) Configured Mouse: PnP-detected protocol: "ExplorerPS/2"
(II) Configured Mouse: ps2EnableDataReporting: succeeded

No output for third code received error message
Hope you can tell me something from the output

If the problem truly is a graphics problem, then I think your ubuntu xorg.conf file won't look the same as the one you posted from the debian install. You should look at it to confirm this and then copy it to the "/etc/X11/" directory on your debian partition. Then restart and try again. You might want to copy your current xorg.conf file to something like "xorg.conf.oldcopy" or something like that. This way you can replace it if the ubuntu version doesn't work. If that doesn't work post "dmesg | tail" and "lspci" and maybe someone will have good advice for you.