How would I dual-boot in this scenario?

If you cannot boot the Win7 DVD, even though you can boot Hiren's (Why?) then you need to wipe the HD to force the DVD to autostart to reinstall.

I don't understand why the DVD won't boot if Hiren's can. Are you being prompted to "Press any key?"

Try writing the ISO to stick using Universal USB Installer which is Linux-based.

Clarification:

The big-ISO Windows 7 repair disc, which contains the installer, gives me a compatibility error when "Repair Your Computer" is selected. The installer - it is working, up to the point where it says it can not install due to the presence of another MBR (C and System, I assume).

The small-ISO which you PMed me, will not boot at all.

Are you sure you burned the correct 64 bit-version?

I've never heard of installer giving that error if it is booted.

I'm sorry that I have upset you, and will try not to take up much more of your time. Once W7 is back with settings & programs, it should be comparatively simple to complete the original goal.

Well, I'm testing the waters in preparation. Small updates where merited...

One of the cloners in Hiren's has this to say about both the OS a.k.a. C:\ and System partitions:

The source volume is not the volume where the current Windows directory is kept.

I can locate the Windows directory in C with a file manager. This may shed some more light on why the W7 Install disk does not detect compatibility.

The software has the option to "make the target volume self-bootable". Knowing what we know about the situation of the C partition, and with the understanding that I intend to copy over C from the external once W7 is running again, I will leave well enough alone with that.

Have you copied out of C your files that you need using Hiren's XP explorer as I suggested hours ago? Instead of replying back that you've done this, or asking any questions about how to do it, you replied instead that you'd done something completely different which wasn't even suggested. Why do you continually do this?

If you've copied out your files, I suggest you run your HD maker's Diagnostics extended scan from the HD tools on Hiren's CD to determine its condition with certainty, then do the Quick Wipe which should also be on HD Diagnostics menu. If not run Darik's Boot and Nuke Quick Wipe.

This should force the Win7 installer to start and begin Clean Install Windows 7. At Steps 6 and 7 create and format your partitions as you wish, ignoring the small boot partition it creates at the beginning of the drive. Then highlight on the first partition after that small 100mb boot partition and click Next.


Please see if you can keep your focus on these steps only. Ask back any questions, but just stay focused on getting these steps done.

Have you copied out of C your files that you need using Hiren's XP explorer as I suggested hours ago? Instead of replying back that you've done this, or asking any questions about how to do it, you replied instead that you'd done something completely different which wasn't even suggested. Why do you continually do this?

That's a bit unfair. I was meant to clone the contents of a drive, and I posted some interesting info taken from a cloner! I understand that you may not be interested any longer in why exactly and mechanically the machine has the problems it does, and would further like me to take things one step at a time, so I'll lay it out for precision:

You may take my post above your latest as confirmation of a successful cloning operation. I will now wipe the HD, run all recommended scans, disconnect the external, and follow provided procedure on reinstalling Windows 7. I will not post again unless it is to declare I have Windows up or to report a serious barrier. Very well, sir, until then...

Copying out your files to backup is not the same as cloning an OS which won't start.

But perhaps you have some other plan to be able to boot a disk to finally repair the OS on another HD, or copy the files out from there, so carry on!

You got the wrong idea. I feel like there is some sort of communication barrier between us, as we keep misunderstanding each other.

See here:

I intend to retain all my programs and settings on Windows 7. I will copy over C from the external once Windows 7 is running. Which folders on the external should I delete to prevent any issues? Windows? Boot?

I'm trying to be as plain and direct as I can. Won't you please give me the benefit of the doubt from here on?

***

Windows 7 has been reinstalled as of this morning. Prior surface test by Partition Wizard and one of the Hiren's diags reported no bad blocks, though CHKDISK found and deleted a couple of corrupted "file segments". Rebooting with the install disc after installation showed that the "Repair your computer" option recognizes the OS. Sorry it took a while, but the wipe was only nominally "quick". With that done, please instruct me on the following.

Please confirm that it is safe to copy over these directories (from the external onto the internal), and that after a reboot my settings and programs will generally have been restored:
Boot (this is apparently a Macrium-associated folder, and seems to have nothing to do with the OS)
MSOCache
NVIDIA
PerfLogs
Program Files
Program Files (x86)
SWSETUP
SYSTEM.SAV (56 MB folder; don't know what is)
temp (Nvidia-related)
Users (after I restart, will the old Start Menu, desktop settings such as Background, and User Accounts at Login be back?)
pagefile.sys (I would like to copy back this file and the one below, but I can't see them in Windows Explorer despite switching Hidden Files to visible)
hiberfile.sys

I am excluding: Windows