This is not the wierdest dual boot problem ever. It is actually a common problem that folks make.
When you install Linux, you want to have both hard drives in the system, with the bios boot order the way you want to dual boot.
If you take the Windows XP disk out, then put it back in after the installation, you can't expect Linux to know about it, can you? You also can't expect XP to dual boot, without making some changes.
You are correct, RedHat 9 does not do sata. It is an old release, before sata support was added in.
So, let's take a look at your hardware. What make and model computer is this? If you built the system yourself, what motherboard is in the system? This will tell us what exact sata interface that you have and support for it with Fedora whatever version.
What make is the pata drive in the system? Why? This tells us the options for formatting your hard drive correctly and getting rid of any MBR which may be invalid.
What you have is a pata drive that either still has the MBR written to it (if you have the bios boot order with the pata drive set first), or you wrote over the MBR on the sata drive (if it is the first in the boot order in the bios) and have a pata drive with mixed partitions on it.
DOS boot disks and using fdisk in DOS will not delete all the information on the pata drive, especially if Linux was installed and a bootloader to the MNR. Not unless you really know what your doing.
"VFS:cannot open root "<NULL>" or unknown boot (8,3).
please append a correct"root=" boot option
kernel panic not syncing :VFS unable to mount root fs
and loads to rubbish... "
Fedora's grub can't find the root filesystem on the pata drive, as the partition setup is most likely incorrect with the multiple attempts to install.
Also, if you took out the sata drive during the installation, then put it back in, most likely the designation of the drives has changed, so Grub can't find Fedora where it expects it.
From all the posts that have been on the forum for Fedora Core 4, I suggest trying Fedora Core 5.
But either way, you need to install Fedora with some changes during the installation with how the bootloader is configured (the order of the drives at boot), as Fedora assumes that you are installing on the only hard drive in the system, unless you tell it otherwise. You must be careful where Grub and the bootloader is installed and have
BOTH hard drives in the system.
Of course, unless you know what you are doing.
Please bear with me. It is difficult to know what you have done with all these installation attempts and manipulations of your partitions. essentually what you want to do is;
1. Get rid of any current partitions on the pata drive.
2. Have both drives in the system, with the bios boot order the way that you will keep it.
No changes after the installation.
3. Install Fedora with the bootloader to the MBR of the drive that is the boot drive, not any other.