The solution to the problem is in two stages (from my experience, as it
always happens to me when installing ubuntu).

1. When booting the computer and the grub menu comes up press the letter
"e" (without quotes). That (as is written under the menu) will enable
you to edit the partition place your Ubuntu is installed.

2. The line to be edited is the first one with the (hd 1,4).

3. The numbers must be changed to be the correct ones where your Ubuntu
is installed.

4. The numbers mean which disk Ubuntu is installed - the first (or
primary) disk is always "0".

5. The second number refers to the partition on that disk where Ubuntu
is installed.

6. In all cases the first partition of a disk is "0".

7. So if you have one disk the number will be (hd 0,something) depending
on the partition.

8. If you have windows as a dual boot the Windows partition is usually
(but not always) (hd 0,0)

9. That's how mine is so the Ubuntu partition on mine is (hd 0,1)

10. You can play around with this ad infinitum, trying out different
combinations. When you get the correct combination your Ubuntu will boot.

11. If I remember correctly you change the combination each time by
pressing "e" to edit and after changing the combination press "b" for
boot to try it out.

12. When you are finally booted you have to permanently edit the grub
menu to remain with the correct combination for future booting.

13. That is done through the terminal and a text editor (with sudo) of
the /boot/grub/menu.lst file.

14. One last comment - you may also have to correct the combination of
the Windows HD reference in the "menu.lst

There may be a more "scientific" (correct) way of doing this but this is
how I've done it many times.

Which drive is Windows actually installed on? Basically it sounds like grub
installed to your boot partition (default) and overwrote the Windows boot loader
or the systen is confused as to where Ubuntu is installed vs where Windows is
installed.

You should find out where Ubuntu has put itself. Best way to do this is to go
into grub from the boot menu to edit an entry and use the TAB key to give you an
idea what drives have what. The command:

Unfortunately, I wasn't able to try out the suggestions, as my last
installation was with WUBI, which didn't produce the GRUB booting menu.

Afer doing a Google search, I discovered that the grub installer doesn't
like some combinations of mixed serial & parallel drives. Versions
before Hardy Heron gave problems if the Windows boot/installation was on
the serial drive. Hardy Heron gave problems if Windows/boot was on the
parallel drive.

The solution suggested was to disconnect any drives of different type to
the boot/Windows drive, so that all drives are the same type. In my
case this meant disconnecting the serial drive, leaving me with two
parallel drives.

I had previously attempted to do this, by disabling the serial drive in
the CMOS, but leaving it physically connected. Presumably the installer
is able to overule the CMOS settings and still detect the serial drive.

After uninstalling WUBI, deleting all the partitions on the second
parallel HD, and disconnecting the serial drive, Hardy Heron installed
correctly.

AFAIK most computers now use serial drives and the installer appears to
have been changed, to assume that this is always the case :-(

First off a caution on the Vista dual boot. Don't expect it to stick. Vista has
a habit of trashing Linux when it updates.

As for the desktop dual boot problems, when you install Linux it makes a
difference where grub is installed to. If it is on the MBR of the first device
and you don't change things it usually works without a problem. However, if you
change things through BIOS or by pressing a key to boot a specific device then
you will be in for a surprise, no grub or a grub that won't work. No grub is a
bigger problem. A broken grub is easy to fix.

When you install Ubuntu it does not give you a choice where to install grub and
if you just press Enter it will install it to sda or the MBR of the first drive.
In order to choose where to install grub you need to click on the Advanced
button on the lower right of the final screen where it reviews all of the
changes, just before the installation begins.

If you have a key to press to bring up a boot menu as many BIOSes allow and wish
to boot that way, you should install grub to the MBR of the drive where Ubuntu
is installed. If you don't have this option and don't change your setup, then
you can install grub to the MBR of your main drive (the one that boots by
default).

The first thing to do is to check if grub Ubuntu is installed. You can do this
from the Live CD. The second thing to do is to re-write grub. You can do this
while in the Live CD.

https://help.ubuntu.com/community/RecoveringUbuntuAfterInstallingWindows

Things to know:
Grub uses a different way of naming drives which is relative to where grub is
installed and uses ordinal numbers (counting from zero). If it is to be written
to the same drive where Ubuntu is it will name the drive differently than if it
is on another drive. The drive where grub is written to is (hd0,0) and the other
one will be (hd1,0). If grub is written to a drive other than where your
installation of Ubuntu is the drive numbers will be reversed. The first number
is the drive number starting at zero and the second number is the partition
number starting at zero. Your setup and how you plan on booting will determine
whether grub works successfully or not.

To confuse things Ubuntu uses a different system such as sda or hda for the
first drive and sdb or hdb for the second drive (or sda and hda). This is
determined by their boot order as determined by BIOS and the type of drive (SATA
or IDE).

I hope that this isn't too confusing. Just try to be logical and follow the
guide.