Help setting up Windows on external hard drive needed, please?

Oct 23, 2020
Dear Anyone.

Mods, if I've put this in the wrong part of the forum please move it. It's just I couldn't think of where else to put it (don't get anatomical!)

OK. I've got Windows XP SP3 on my internal hard drive, I have to stick with that because of my disability software. But I wanted to be able to boot from Windows 7 as well, so I've got a 1T hard drive in a caddy. The dumbass question, cos I've never done this before, is if I put the Windows 7 files on the external drive and double-click on the .EXE to start the installation process, can I GUARANTEE it will install on the external drive and not look for Drive C - my INTERNAL drive - and install on that, destroying all my files? I mean they're mainly backed up but I REALLY don't want that to happen.

How do I make absolutely certain Windows 7 installs on the EXTERNAL drive and doesn't backfire, looking for the internal one and installing on that instead? I've no idea if that does happen, but I mean Windows is usually on Drive C so I wondered if the installation program always looked for Drive C regardless of where you put it/were firing it up from.

Sorry for the noob question on a forum like this, but there you go, this is why I joined, to ask this.

Just had a thought - yup, framed it before it got lonely! If I upgraded my disability software soon so it cn run in Windows 7, would I then be able to use the external hard drive I've now - with your help - got Windows 7 on as an INTERNAL drive, by just putting it inside the machine? Or if it's had Windows installed on it as an EXTERNAL drive, does it EXPECT to be an external drive, meaning you have to reinstall Windows on it if it now becomes an Internal drive?

Yours hopefully - please go easy on the geek-speak in the answer, I try my best but I can't wrap my head around all this tech. that easily -



Sep 10, 2020
IF you do not have windows 7 on a usb key you can

One way to be absolutely certain is to have an Windows 7 iso installer on a usb key:

And after closing your computer, physically unplug the hard drive you fear you could mistakenly select has the installer target during the windows installer wizard, plugging only the harddrive you want to install it on.

Other tutorial that can be followed to create the bootable USB from an iso or dvd and install from it:

If you have a DVD, you can install from your DVD with only the target hard drive plugged on as well, it can require for you to go in the bios to put the DVD above the drive in your both order (it is explained how to in the tutorial)


Fully [H]
Aug 3, 2004
FYI - Windows 7 running off an external USB Drive is not going to perform "fantastic" by any means, especially if you start copying files around while using the OS?

WHat is the name of your disability software? If it supports a newer version that supports Windows 7 or Windows 10, i presume the upgrade costs you money?