|If I read your post correctly you have an older drive (with XP-Home) as master to a new hard-drive (with XP-Media Centre).|
You can boot to the older OS/installation; but cannot boot to the newer drive (XP-MCE)?
Presumably the boot.ini (on the current older drive set as Master) does not include a reference to the newer drive/XP-MCE; and if this is correct then no way you can boot to it...; at least with it set as a Slave to another drive which is set as Master...
A couple of options various come to mind:
Install a third-party boot-manger util; or tweak (as in edit) the boot.ini to achieve the required entry enable a dual;-boot
I'd be less inclined to use an add-in util as it's really not necessary; as tweaking the boot.ini can be done at least three ways.
Boot as per “norm” to XP on current master; locate/copy the boot.ini (it’s in the c: root and maybe a hidden file) on the current Master drive to somewhere safe (just in case…) – usually to a floppy/usb-stick/CD; and also print a hard copy of it.
Next via Explorer access the (second/slave) MCE drive and locate the boot.ini there (for that installation) – it’s also in the c:\ root and again may be a hidden file; copy it to somewhere safe.
Having found it (the MCE boot.ini) open it via Wordpad/Notepad (or even Word). Again to make things easier later - print a hard copy of this boot.ini and keep it to hand; you may want to refer to it later… Note carefully the contents of the line that refers to the XP-MCE installation (on that drive). There will be a line that refers to default OS to boot; and another below that is more complete and (likewise) refers to the OS installed on that drive.
Copy that line.
Now access and open (again via Wordpad/Notepad etc.) the boot.ini on the current Master drive (for the XP-Home installation). This is the boot.ini you will edit to include the ARC/path statement for the XP-MCE installation.
Paste the entry you copied from the XP-MCE boot.ini to this XP-Home boot.ini. It will go in below the entry already there for XP-Home.
This (XP-MCE) line will have a reference to rdisk(0); change that to read rdisk(1).
Be sure you change the rdisk(0) entry for the line that you have just copied over (for XP-MCE) – and NOT the one for XP-Home…
Save changes and exit… You now have boot-menu that lists both installations.
Reboot system and all things being equal you will be able to choose either installation to boot?
You can also manually enter (write) the required line into the boot.ini on the current Master drive – using the details on the hard-copy of the XP-MCE boot.ini as reference; but ensuring the rdisk(0) value is entered there as rdisk(1) – for that XP-MCE entry – only!
If you are familiar with the uses of Recovery Console you can use its bootcfg util to locate any other NT/W2K/XP installations in the system overall and them to the boot.ini on the current Master driver. It may be easier than the above manual (hunt/find/copy/paste etc…) approach? More on the bootcfg approach see:
I have to say that I too am surprised you managed to get XP-Home from another system to boot OK in a new location – without (apparently) any tweaking etc..?