How do I install Windows 7 on an external drive, and then run that drive as an internal drive on another computer?

[u/Damocci]

I have an unusual query.

Someone I know has an ancient computer running an IDE hard drive, and his USB ports are problematic, so I cannot install Windows 7 using a bootable USB stick. So I would like to put that IDE drive in an external enclosure and install Windows 7 onto it using my new Windows 11 laptop.

Thereafter, I would like to place that IDE drive inside his tower computer so that it boots and runs without errors. Is this even possible? If so, how do I do it?

System specs: It's a Compaq Evo 310DT running Windows Vista with a Pentium 4 CPU, a 40GB IDE hard drive, and I am not sure how much RAM he has.

[u/Froggypwns]

From what I see online that computer has a DVD drive. The easiest thing to do would be to burn Windows 7 to a DVD and use that to install.

[u/Damocci → u/Froggypwns]

His machine has a CD-ROM, not even a DVD drive. I happen to have a very old copy of Windows 7 on disc, but unfortunately it's a DVD.

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[u/ForgottenButHere]

There is an application called WinToUSB that hat would probably work. That said, you’ll need a usb to ide adapter. For my time and money I’d probably find another computer to buy. You can probably find a 8th or 9th gen Intel something or other for less than 100 bucks.

[u/iamofnohelp]

If memory is what it is. Do the install and when it goes to reboot shut down. Then swap the drive into the correct locating and let it boot up.

But this is a horrible idea and not recommended.

Old OS that going to be difficult to use in 2026, not secure. Plus that pc is horribly slow.

Bet you could find a used pc that's significantly better for cheap or free.

[u/Damocci → u/iamofnohelp]

That sounds like a good idea. I will try that and shut down the first time it wants to reboot, and I will visit the owner over the weekend to see if it works out. I was worried that if I complete the installation via my laptop, there would hardware/driver compatability problems that cannot be resolved because the owner doesn't even have internet access. If all else fails, I'll have to see if I can source a reasonably priced second-hand PC for him.

[u/PrivateParts2020 → u/iamofnohelp]

I've done this before. Not elegant, but it works. But it is important to make sure that drive is set to the same mode on both PC's. On an old PC, I would assume it would be IDE and not AHCI. And make sure secure boot is off and you're using a legacy BIOS on your PC when you start the install.

[u/MasterJeebus]

Depends on your pc, if it has csm and can boot to legacy bios you could install Windows 7 on it. But then it installs default drivers meant for your pc not theirs. There may be issue with that.

But looking at that pc it was designed for XP. So performance on 7 may be slow. Also you need bigger drive 40GB not enough for 7. Unless you avoid all its updates? I have seen 7 sp1 fully updated consume 45GB. You also need sufficient ram. I have run it with P4 2.8 Ghz HT and 2GB ram. It was ok but i wouldnt run it on less than 2 GB ram.

Best thing you can do is find 32 bit light distro for it.

For usb find pci card for additional usb ports.

[u/Damocci → u/MasterJeebus]

"But then it installs default drivers meant for your pc not theirs."

This is precisely what I am worried about. The good news is that the owner is an old person and he will literally only be using the PC to listen to music and perhaps watch a movie once in a while. His machine was running Windows Vista, so I don't think Windows 7 should pose much of a problem.

[u/klaus666]

Ooh, I actually had to do this once! If you put the Windows install files on an internal hard drive, then set it as a bootable disk, you can install it directly from there. This should help

[u/Damocci → u/klaus666]

Brilliant! This is exactly the kind of solution I'm looking for. Thank you!

[u/Redjeepkev]

Just burn it on a dvd. You are baking this way harder than it needs to be

[u/Damocci → u/Redjeepkev]

The situation is worse than you realise lol. This PC doesn't have a DVD drive. It has a CD drive. Sigh. I don't know why I am bothering trying, but I feel sorry for this guy. He is an older, simple man, and I feel I must try.

[u/senpaisai]

Won't work. You can't install an OS to an external drive anymore unless the OS supports persistence. Linux does but Windows doesn't. Gonna have to burn the Windows ISO to DVD or set up a PXE network environment ...

[u/Damocci → u/senpaisai]

DVD won't work. The computer only has a CD drive. But the PXE network suggestion could work. Thanks for the suggestion.

[u/senpaisai → u/Damocci]

Then iVentoy might be useful here. I haven't tried it, but I've heard it makes setting up a PXE network environment a breeze and works just as good as vanilla Ventoy ...

[u/socaldisney]

You’re going to spend $30+ on that adapter when you could get a refurbished pc off of amazon for around $120 that runs windows 11 and has much better specs. That would be a lot better option unless there’s some archaic software that is required. And even then, you could just run a windows 7 vm on the new windows 11 machine.

[u/Zealousideal_Fly8402]

D00d you are way better off upgrading the system. Do you realize how ancient 40GB IDE drives are? Nevermind the terrible other specs.

You could probably even find a free charity system over in r/homelabsales or r/homelab...

[u/Damocci → u/Zealousideal_Fly8402]

I fully agree, but this PC belongs to an equally ancient person who cannot afford a newer system. I'm basically trying to help him out in an act of charity.

[u/KeysStickler]

1. That system is useless for the application. That IDE HDD has a rated life of 3-5 years.
2. Have the old person buy a MUCH better used system with SSD and simply install Chrome OS flex, since they most likely only need to check email and use a browser. No viruses and no complexity.

[u/Onoitsu2]

OK so what you want to use is an app called WinNTSetup. You will point it to your Windows install files, and the MBR prepared USB drive partitions for which should be the boot and data partition respectively. You can apply a custom autounattend.xml (https://schneegans.de/windows/unattend-generator/), and inject drivers for that specific computer when WinNTSetup is directed to a folder holding them as well.