I think you are having issues with the Vista Boot Loader. It no longer uses a "Master Boot Record" (MBR) as with Windows XP or Win2K3.

Try reading up on the following links about a free app called "EasyBCD":

Download EasyBCD at the bottom of the page: http://neosmart.net/dl.php?id=1
Documentation on what it is and its uses: http://neosmart.net/wiki/display/EBCD/EasyBCD+Documentation+Home;jsessionid=E7EB8273411599C42351B4A465CDC6D0
Linux specific documentation: http://neosmart.net/wiki/display/EBCD/Linux

One issue you'll find a bit more complex is creating a partition large enough for your linux install, which depends on if you are using either an additional harddrive (which should be quite straight forward),
or if you are trying to install on the same drive with Vista installed by an OEM (where you might be dealing with a recovery partition and other hidden partitions). Vista can shrink partitions,
but you need to be careful with the order of partitions and may need to create an "extended" partition.

There are a number of helpful sites referring to gparted. But it probably is easiest installing Vista from scratch on a clean HDD, and define the partition size for Vista (download and install "EasyBCD" at this point), then install CentOS, making sure you use the advanced settings for where to place the grub loader. Next boot into Vista again and use the installed EasyBCD app. Instructions are in the above links.

Hope that helps...

Thanks for the reply.

This is the output from fdisk -l

Disk /dev/sda: 320.0 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders
Unis = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 * 1 27707 2225528480 7 HPFS/NTFS
/dev/sda2 37778 38913 9124920 7 HPFS/NTFS
/dev/sda3 27708 27719 96390 83 Linux
/dev/sda4 27720 37777 80790885 5 Extended
/dev/sda5 27720 37777 80790853+ 8e Linux LVM

and here is grub.conf

default=0
timeout=5
splashimage=(hd0,2)/grub/splash.xpm.qz
hiddenmenu
title CentOS (2.6.18-92.1.18.e15)
root (hd0,2)
kernel /vmlinuz-2.6.18-92.1.18.e15 ro root=/dev/VolGroup00/LogVo100
initrd /initrd-2.6.18-92.1.18.e15.img
title CentOS (2.6.18-92.1.13.e15)
root (hd0,2)
kernel /vmlinuz-2.6.18-92.1.13.e15 ro root=/dev/VolGroup00/LogVo100
initrd /initrd-2.6.18-92.1.13.e15.img
title Other
rootnoverify (hd0,0)
chainloader +1


Any suggestions are appreciated.

It's not quite clear from the original posting but anyway. If the second installation was actually done on its own space, then editing grub.conf does no good. You need to find out where (which partitions) the second copy of CentOS was installed and remove them. Perhaps, posting fdisk -l and the content of /etc/grub.conf may give us some clue.

Edit /boot/grub/grub.conf and remove unneeded OS entries from there. I noticed, that /boot/grub/menu.lst is used also on some systems.

http://www.redhat.com/docs/manuals/linux/RHL-9-Manual/ref-guide/s1-grub-configfile.html

Real a newbie to this OS. So, recently we salvaged a desktop loaded with Vista OS. I have setup half of the harddrive volume for Centro's OS using unallocated volume recaptured from Vista and installed Centro 5. My thought was dual OS desktop. Unfortunately we had some difficult and re-ran the install twice. All seems to have installed. But in looking at the OS list. There are three OS's available The old Vista as other and two Centros are listed. The second installed Centro is unwanted. How will we remove this unwanted installation?