I have a loaner laptop that has MS Windows with locked down permissions. It works okay for what I need to do, but I started wondering if there was a way to install a separate Windows OS on a separate hard drive to do what I want to do on it.


I wish I could use VirtualBox or VMWare, but that is not an option (I even tried VBox portable).

External Drive

My next trial was see if it was possible to install Windows on an external drive, and then plug that drive in and boot from it whenever I wanted my own OS. After a few Google searches, I see that is not really a possibility.

Swap Primary Drive

Another option, would be to get a second internal hard drive, take the existing HD out, and install a new Windows OS on the secondary HD. This would mean swapping the internal hard drive each time I want to switch OSs - doable, but not very convenient.

Dual Boot

The laptop has an expansion slot where a second hard drive can be plugged in quickly. I thought about Dual booting, but I don't want to mess with the MBR on the primary hard drive. When I have to give the laptop back, I don't want a dual-boot screen to popup.


Is there a way to have 2 hard-drives on a machine, each with it's own OS, and maybe use BIOS settings to have only 1 hard drive active at a time? That way both hard drives could be physically connected, but only one would actually be active at a time.

I basically want a second OS that does not (can not) affect the existing OS in any way, and can be removed at any time without affecting the existing OS. The secondary OS does not need any of the files on the main hard drive - it's basically like having 2 separate computers using the same hard ware...

Is this possible, or would it be easier just to go out and buy a different laptop?

Thanks in advance!


I just discovered that my BIOS allows me to pick (at startup) which hard drive I want to boot from. I poked around in the BIOS and there is not a place to disable certain devices, like the primary hard drive. My only concern about plugging in a second hard drive and installing Windows to the second hard drive is that it will mess with the primary hard drive, or add a bootloader screen to pick which windows install to use.

My thought would be to physically unplug the primary, plug in the secondary and install windows to the secondary. After the install is working properly, I can plug the primary back in and use the BIOS feature to determine which drive to boot to. Is there any way after I have 2 separate installs on 2 separate hard drives that one of the installs could mess with the MBR on the other drive?

  • Check if you can disable attached devices in BIOS that way you can just disable the primary, boot with just the secondary enabled, and install the OS on the secondary. Then you simply just have to enable the drive you need and disable the one you don't in bios. You won't ever have to worry about messing up whats on the other drive while booted to the secondary drive. – Not Kyle stop stalking me Feb 18 '11 at 17:09
  • I was searching Amazon for the expansion hard drive, and here is one of the comments on the product page: "I use this drive to run my old copy of Windows XP, and the internal drive to run Windows 7. You can hit F7/F9 during boot-up to select which drive to boot from. No issue booting from this." That looks like exactly what I want... – BrianH Feb 18 '11 at 17:13
  • nope. the mbr on the first drive won't be affected. – Michael Lowman Feb 18 '11 at 19:33

I recommend buying a cheap laptop of your own instead. Why play around with someone else's property at all? A new HD will cost, what, $200 for a decent one. A laptop in full should cost less than $500. A netbook would be $300-400.

  • There just doesn't seem to be a non-intrusive way to do this, so I think this is the best answer... Thanks! – BrianH Feb 21 '11 at 14:09

There IS in fact the possibility of booting (at least) Windows XP from USB. I have done it, but it is a pain in the ... You will have to install the windows on an internal drive at first, afterwards you can copy it onto another drive and boot it (this fails). Then you will have to get an second windows or an BartPE and edit the registry of the Windows on the USB-Device. Afterwards it will boot (usually) but if you put in an USB-Stick it might undo the registry editing and you will have to edit the registry again. If you really wanna do this, i could search the article from the german computer magazine and translate the interesting parts.

I'm sure it works, because i have done it myself. A friend of mine broke is laptop HD and had no money to buy a new one, thus i installed Win XP on his external 3.5" HD, he used to boot his Win XP from this HD for half a year or so...

If anyone else is interested in this, i could do it, too.

I just found this article that one might work, too. It sounds at least reasonable. But as i said is a lot of work.


Why not simply make a boot CD? Then you just boot whatever OS you want from the CD and still have access to the files on the original HD.


Get a large internal hard drive - say 500Gig ($100). Clone the existing drive and then wrap it up and put it away. On the remaining space, put on your secondary OS as the dual boot. When it comes time to return the laptop, remove your drive and reinstall the original.

  • I do like this idea... too risky in this situation, but very nice idea! – BrianH Feb 21 '11 at 15:58

I don't know who your "loaner" laptop is from and under what sort of terms your loaner was provided. Clearly the entity making the loan had some reason for locking down the operating system. Any of the various scenarios you've described involving switching the existing hard disk or adding a second hard disk could be considered a breach of the terms of the loan. You could find that you now own the laptop (at probably an inflated price) or that you are unemployed (if the laptop belonged to your employer).

Your best bet would be to buy yourself a cheap laptop for a little bit more than what the second hard disk would cost. If you do that, you only have to worry about voiding the warranty on your laptop.

  • It's for my classes - not an employer... – BrianH Feb 21 '11 at 4:27
  • So it is something provided by your school? If that's the case then you could find that you are buying the laptop from them if you open it and add or change components. – Mike Chess Feb 21 '11 at 5:47
  • Before I started looking at this, I was imagining something as easy as plugging in an external hard drive that had a separate OS on it, and booting into that OS. I don't even want/need to see what is on the other harddrive/OS, and I'm not trying to get around their security. I just thought that if I had the laptop, I could use it for 2 different purposes - one for classwork, and one for personal use. If I was booting to and modifying my own OS, and it could be "undone" by simply unplugging a USB cable, nothing has changed on the original machine... I wasn't trying to do anything sinister.. – BrianH Feb 21 '11 at 14:12
  • Since it is not as easy as "plug in a new OS" then yes, you are right, I should not mess with their system. – BrianH Feb 21 '11 at 14:14

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