How would I dual-boot in this scenario?

That's technically impossible as far as I know. You can't merge an unbootable (or any) OS into a reinstall. I would not even copy over settings as they are a corruption path defeating the purpose of a Clean Reinstall.

I tried to tell you this.

If you need your old install then there were other steps I offered to try everything possible to get it started. I suggest you go back to the top of the thread and work through every step given on your clone, plugged in by itself, leaving out your lengthy flights of fantasy which interrupted the flow so badly you've likely missed the fix.

If that's the case, then I suppose I have much work ahead of me in manually restoring everything piece by piece. I'll post if I encounter troubles.

Perhaps we'll postpone that XP business for after New Years'...

As long as you stick with the tools and methods given in Clean Reinstall - Factory OEM Windows 7
you'll have a perfect install.

I've tried to figure out a solution, but I'm finding certain major issues to be insurmountable.

1. Windows 7 will only permit very low resolution settings, a maximum of something like 1200 x 1000 or thereabout. Before this incident, my setting was 1900 x 1600 or thereabout. Everything is also ineffably uglier, somehow.

2. Windows 7 can not find my adapter/DSL router. It is attached to the computer via Ethernet and is also wireless capable. In fact, Hiren's BootCD can connect to the Internet through it; this post was typed on Hiren's browser. No amount of reboots (of either PC or router) can induce Windows to recognize the router. It stubbornly refuses to recognize the presence of any network hardware.

3. I set up a dummy account to test how Windows would react to my copying in my old Desktop, which amounted to at least 3/4 of the content on my old install. I had to do this from Hiren's BootCD, as Windows does not permit me to access the folder for my old profile on the external. I receive a prompt to gain permissions to access the directory, but no developments come from clicking "Continue". I checked the permissions and set them to full where available, yet still the same nonsense.

3.a. The dummy account is broken. Near any operation I attempt to perform returns an error claiming a lack of privileges on my part. As the dummy account is has admin privileges, this is clearly related to the aforementioned bug. While the dummy account is no loss, what it all amounts to is that I am left without means to access the majority of my files and programs from or within Windows.

I'm at a loss.

Did you follow the step in the tutorial which says to put your wireless/ethernet driver on stick or CD so that if it isn't provided during install you can install it to get online quickly? Do that now.

First run the adapter driver's installer as Adminstrator, watch the connection icon in bottom right system tray for network to show up to connect.

If that fails what shows up under network adapters in Device Manager? For the related device, from the Driver tab>Update driver choice, browse to where the driver installler unzipped the driver files to pick up the driver. It may take some trial and error.

If this fails try it for the other network adapter. I've never seen it not work for both. It has nothing do do with the router or modem unless one or both of them need rebooting. Try ethernet with wire connected directly to modem.

Drivers! How could I not have thought of it.

I installed a slew of drivers (though not to my knowledge any for motherboard or chipset - can't figure that out), and items 1 & 2 have been resolved.

#3 is still troubling me, however. I don't have proper access to the majority of my files!

Further, I will need to reconfigure or even reinstall most of my programs. I really can't start on that in earnest until I have one solid user profile set up with all my old User Profile content.

To be more specific, it's something like this.

Changing sharing properties does nothing, and in the owners tab for advanced security settings the owner is listed as:

Unable to display current owner.

The folder is listed as being 0 bytes big, though the partition as a whole is still the same size so the contents must still be within. They in fact are, as I can see them in Hiren's and am able to copy them over. Attempting to operate on the copied files within Windows leads to the error described in my previous post. What be the prognosis?

It's nice when things come together of their own accord. I gave the machine another reboot and found access had spontaneously been granted.

Merry Christmas indeed!

I'm assuming since you had to install a bunch of drivers that you didn't follow the instructions to install all of your Important and Optional Windows Updates first thing until all the necessary rounds were completed with reboots?

Try Take Ownership Shortcut on the XP file backup.

If that fails since you know that it works boot into Hirens XP Explorer to copy the files into the Win7 User folders thereby bypassing all permissions.

I don't know what you mean by setting up a Dummy account. You should have set up your User account during install. Will you please not mess with this to try something outlandish like everything else you've done in the thread, but instead do what everyone else does which is populate the User folders, install your programs?

Oh sure, that's what I had done earlier - but the noted bugs wrecked everything. Hopefully that's all in the past now.

I'm prepared to take on this project once more. This time, I'm considering a different approach:

1. Wipe the external.
2. Make a disk image backup of my W7/internal HD (which is almost exactly as it used to be by now) onto the external.
3. Clone the XP drive onto the internal, using Macrium.
4. Ensure all partitions are inactive on the internal, using Partition Wizard.
5. Using Macrium bootable media, reimage the backup from the external onto the internal.
6. Ensure the reimaged partition containing W7 is active, using Partition Wizard.
7. Boot normally, with the expectation that W7 will boot.

I think I've got it this time.