Before I begin, I did post this in the XP forum also. I did this because I need a response kinda quick. If that bothers anyone, then feel free to remove one of these posts. It actually involves both OSs, so technically I can do this
I'm going to start off with my whole process on how I did this. I am performing this in a Compaq SR5310F Desktop computer that originally came with Vista Home Premium:
Within Vista, I opened the Disk Management utility. I then shrunk the volume and left myself with exactly 40GB of unallocated space for my XP installation. I then booted from my XP Pro cd, selected that unallocated space, formatted it using NTFS, then installed XP. It copied all the files fine, but when it reboots to launch the GUI of the installation, I get a message saying, "Error loading operating system"
I figured something like this would happen because XP cannot recognize Vista and I have just replaced the vista boot loader with the XP bootloader. So, I popped in my Vista home premium disk, went to the Startup Repair, let it run. It told me that it fixed any problems and that I should reboot my computer. I figured it had replaced the bootloader with Vista's and it would boot to Vista...but I am still getting the "Error loading operating system" message.
I have tried installing these two OSs a couple different ways...basically the only differences were where I created the partition for XP. I tried creating the partition for XP while installing vista also, but still have the same results. I tried just installing XP in the unallocated space instead of defining a drive letter before installing, but still the same results.
I have a feeling that if I installed XP first, and then vista, the vista bootloader would then be installed and this would all work. but i know its possible to do this with vista installed first and I want to know how. Am I missing something??
Every tutorial i am looking at is doing the same thing I am doing. But in the tutorials, after XP has copied its files over to the partition, it reboots and actually loads the GUI of XP, and then the rest of the installation continues. They then have XP installed and it works fine. Only thing left is to reinstate Vista's boot loader.
With me, I can never get to the GUI portion of the XP install. After XP copies its files and reboots, I just get this message. I dont understand what i'm doing wrong.
my best guess
The MBR does not know what OS to load, you will need a bootloader. You will need to fdisk and install XP first then install Vista. But I doubt Compaq restore disk allow that. I never liked too install 2 OS's on one hard drive since if you get hard drive falure you loose both OS's.
read up a bit, and maybe check Compaq user groups for a user that allready did what your tring on the same model you have.
yea, i am going to try installing xp first so then vista's bootloader will overright xp's instead of the other way around. it still doesnt make any sense because xp should be loading with no problem after installation...and then i just need to install vista's bootloader afterwards.
also, i am not using any disks supplied by compaq, i am using an OEM XP Pro SP2 cd...so i should be ok there.