Setup a Dual Boot Window 7 (main), XP Pro secondary

It depends on which drive you want as the host/boot drive. If you swap data cables around between drives you can have the 7 drive seen as "Disk 0" with XP as "Disk 1" with G as the one plugged into the 3rd sata port if all are sata drives.

If you have an ide drive in the mix by chance the Windows installer will always look there first! For seeing the 7 drive as default/host/boot you would either have that plugged into the first port or unplug the G "Disk 0" drive and run the startup repair tool to recover the boot information. From there you then simply need to copy the XP boot files mentioned before over to the root.

For editing the boot.ini you first right click on the copy at the 7 root and uncheck the "read only" box followed by clicking on apply. then simply double click on the file itself to see that opened up with Notepad to make the needed change to the "rdisk()partition(1)" information there.

That will depend on how the drives are arranged however to see work. Once the edit is done you save as "all files" not "txt" to see that overwrite the copy of the boot.ini made on the 7 drive.

When you have decided which will be the default that then is set as default in the bios boot order. Presently then XP is seen as HD0 and using the startup repair tool when booting from the 7 dvd should see 7 mbr entries and boot files placed there being sata 1 on the system.

With the G drive XP was installed onto that replaced the original 7 mbr entries and why the "missing bootmgr" message was seen. Now it will depend mainly on which drive you will want as the default boot device. If you want the 7 C drive as default you would need to swap cables with the XP drive making that HD0 instead the present G first configuration before making any corrections.

With the present layout the startup repair tool as well as the "Fixboot" and "Fixmbr" commands entered at the command prompt while booted live with the 7 dvd would see the boot information rewritten. You will then see the "recovered" for 7 once the dual boot is configured leaving the XP drive as host/boot. That avoids the need for a repair install of 7.

The ideal option if the 7 install was recent and not loaded up and wanting 7 as the host.boot drive instead would be seeing that plugged in sata port #1 and made the default drive. If needed in the event the boot repair items mentioned should fail to work you see a clean install of 7 later to add XP in as a boot option with the EasyBCD tool.

The Disk Management tool would then show "Disk 0 (C) 7", "Disk 1 (G) XP Pro", "Disk 2 (D) Storage". This would leave the XP drive as a secondary OS drive rather then the host/boot drive for the system.