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How do I set up Windows 7/Vista/XP to dual boot on a new system?

This Tutorial addresses:
  • Windows Vista
  • Windows XP
  • Windows
  • system
  • new
  • dual booting
  • 7
  • booting
  • Dual
alberthrocks
By ,
Introduction
What is dual booting? Dual booting is the ability to boot into a select installation of an operating system from two or more operating system (OS) installations. Simply put, it is being able to boot into multiple OSs, one at a time. It is important to note that "dual boot" does not mean you can have Windows XP and Windows 7 running at the same time. Rather, it means that you can reboot your computer and switch to either Windows XP or Windows 7 to boot up when your computer starts.

Do you need dual booting? The answer is simple: only if you need to run two OSs at once. Often, this is not the case, but this may be desired for certain people.

Dual booting is not limited to Windows OSs only. If you are a Linux guru, Linux can be installed alongside Windows as well. However, Windows-only dual booting is only covered within this tutorial.

Let's get started!

Prerequisites
We need to know a few things:

  • Is this a fresh install or an existing install? A fresh install is when you are starting off with a completely new system, with a blank hard drive. If your hard drive has an OS on it already, you are performing an existing install. This tutorial is only if you are doing a fresh install. If you are not doing that kind of install, see my other tutorial for instructions on how to set up a dual boot configuration for an existing system.
  • What are the disk space requirements for all of my operating systems? If you are installing Windows 7/8, you would generally need around 16-25 GBs of space. Vista may require 10-15 GBs of space, and XP may require 2-4 GBs of space. These are the entry-level requirements for each OS, and you should plan to have 10+ GBs extra alloted for each OS. Failure to do so could lead to problems in the future.


  • Finally, we need to have:

    • A reasonably sized HDD to hold 2+ OSs
    • Installation media to install the OSs
    • A CD/DVD drive or USB port if the installation media is in the form of a USB flash drive


  • This tutorial assumes that the system is working properly and does not have any problems. To be specific, your system should be able to display the BIOS screen, and end up at a prompt where it says something similar to "Boot device not found". If not, your system has problems and should be fixed before attempting these instructions.

    That said, let's get started!

    Steps:
    (Note: The screenshots below were taken in a virtual machine. Things should be pretty much the same as on a real machine, but there may be slight differences depending on your hardware configuration.)

    1) Install your older OS first.
    In my example, I will be installing Windows XP and Windows 7 in a dual boot configuration. Windows XP is obviously the older one, so I will install that first.
    If you are installing the same OS version for both OSs, just install the OS twice and begin with that OS version. (If I'm installing two Window Vista installations - scary - I would install Window Vista right now, and then install it again after the first installation is complete.)

    a) Start the setup!
    Insert your CD/DVD into your drive (or your USB drive). Then boot your computer. If it doesn't start the Windows Setup, change your BIOS settings to allow the CD/DVD drive and/or the USB drive to boot first.

    Once the setup starts, select your desired options. Continue until you get to the setup options/partitioning screen. The next step will deal with that screen.



    b) Select "advanced" setup option.
    Once at this screen, select Custom (advanced). This should take you to the partitioning screen.
    On the Windows XP screen, the setup options screen does not exist. The partitioning screen below should look similar to your current screen.



    c) Partitioning
    Partitioning is where you create partitions on your hard drive. Partitions are really what they sound - actual partitions on your hard drive. (Still don't get it? Think of it as an acre of land, split up into sections for a farm, a lake, a house, etc... that's basically what is going to happen to your hard drive.) Different OSs operate within each partition. You can't install multiple OSs in one partition - it simply doesn't work. (In the farm example - imagine trying to build a house on top of your barn!) Therefore, we need to "partition" your hard drive so that we can install two (or more) Windows OSs on your system.

    First, decide which OS will be your primary OS. For us, the obvious choice is Windows 7.
    (Disagree? Windows XP is sorely outdated, and you could be at risk for severe security problems from using it. Windows 7 is a very stable, rock-solid OS, and it's 1000x better than Windows Vista - I promise!)

    Once you've figured out which OS you want to be the main OS, lookup the space requirements for that OS. The space requirements are generally in GBs. (I've listed an estimate above.) Note the space requirements for your main OS.

    Now lookup the space requirements for your other OS and note them.

    Your first partition should hold your main OS, and should generally be larger than the other partitions, since this is your main OS that you will use. Generally, you would need a 70-30 split of the hard drive. If you intend to use the other OS a lot as well, you can do a 60-40 split or even a 50-50 split. Pick the ratio based on your intended usage of both OSs.

    Once you have decided, it's time to do a little math!

    Partition #1 size: First percentage * HDD size
    In my case, it's 70% * 50 GBs, or 0.70 * 50 = 35 GBs.
    Check to make sure it meets the requirements of your main OS. In my case, I'm using Windows 7 as my main OS, and I have at least 16-25 GBs of space, so I'm good.
    Check to make sure it meets the requirements of your other OS. In my case, I'm dual booting with Windows XP, and I have at least 1.5 GBs of space left over - plenty.

    Partition #2 size: Second percentage * HDD size
    In my case, it's 30% * 50 GBs, or 0.30 * 50 = 15 GBs.

    Write the sizes down and label them as partition #1 and partition #2.

    Now let's look at the setup screen. My HDD is 50 GBs, and the XP setup is displaying it as 51199 MBs.

    To ensure we convert the MBs to GBs correctly, we need to determine what unit the setup is using.

    MBs -> GBs can be expressed in two ways:

    • 1 GB = 1024 MBs
    • 1 GB = 1000 MBs


  • If you're unsure, the former is usually the standard. (The latter is just used for quick calculations, but doesn't represent actual size.)

    To verify, we can take the amount and divide it by each to find which one is closer to our ideal 50 GBs:

    • 51199 MBs / 1024 MBs/GB = 49.999
    • 51199 MBs / 1000 MBs/GB = 51.199


  • Without a doubt, the 1024 MBs/GB is correct.

    Therefore, for each partition, I need:

    • Partition #1: 35 GBs * 1024 MBs/GB = 35840 MBs
    • Partition #2: 15 GBs * 1024 MBs/GB = 15360 MBs
    • Total: 51200 MBs


  • Note that the total is 1 more than the total size. Just subtract one from the last partition, and we get:

    • Partition #1: 35 GBs * 1024 MBs/GB = 35840 MBs
    • Partition #2: 15359 MBs
    • Total: 51199 MBs


  • NOTE: If your OS is Windows Vista/7/8, you may be suggested to have a "System Reserved partition". It's up to you to decide whether you want this partition or not. If you want to go with the default, simply subtract 100 MBs (or whatever size) from the first partition.

    Write these values down. Now we're ready to partition!

    Windows XP's setup is still in the console ages, so we'll have to use our keyboard here. For new versions of Windows, the setup should be much more user friendly. (See below for a good idea on how to use your mouse and keyboard to add partitions.)

    NOTE: The setup for new OSs (Vista/7/8) applies partition changes immediately, so beware! Unlike Windows XP setup, changes are applied as they are made within the partition dialog.

    Hit C, and enter in the first partition's size. For me, it was 35840 MBs.


    Once done, hit ENTER. It will return to the partition list.


    Now highlight the unused space (hit the down arrow key), and hit C.


    Woah, how did the max size get smaller? It's now 15351 MBs instead of 15359 MBs!

    It turns out that Windows setup is lying a tad bit to you. Indeed, you have 35840 MBs of free space... but that's not true.
    In reality, the partition takes up more than that from metadata in the partition to help organize the files.
    Also, the partitions need to be aligned to a certain amount in order for things to go smoothly, and therefore it cuts off
    at a certain part.

    Therefore, we accept the default of 15351 MBs, and end up with this.


    d) Finish the setup!
    Highlight the second partition, and hit ENTER.


    We want to do a thorough format of the NTFS file system, so press ENTER.


    Don't panic at this screen! It may seem like the setup is installing to the bigger partition, but it's just formatting both of them.






    Once done, it will immediately begin installation.


    Reboot, but don't remove the CD/DVD/USB! Then complete the setup.


    e) Verify the installation...


    Let's take a moment to admire Windows XP for a second. If we look at our drives right now, we can see that XP was successfully installed on the second partition of the hard drive, and our first partition remains blank. (C: is usually the first partition, D: is usually the second.) Note that C: is completely empty. If we open D:, there would be a warning about system files. Verify that this is the case. If you installed on the wrong partition, go back to step one.


    f) Actually setup the system!
    Now install updates and programs on the OS. Do not proceed until you are done!

    2) Install your main OS.
    Wow, a lot of work for the first OS, which isn't even our main one! No worries - your hard work in the first step will pay off!
    This time we will install our main OS. In this case, we will install Windows 7.

    a) Start the setup!
    Insert your CD/DVD into your drive (or your USB drive). Then boot your computer. If it doesn't start the Windows Setup, change your BIOS settings to allow the CD/DVD drive and/or the USB drive to boot first. This time, you may need to hit a key to boot from your installation media.


    Once the setup starts, select your desired options. Continue until you get to the setup options screen. The next step will deal with that screen.

    b) Select "advanced" setup option.
    Once at this screen, select Custom (advanced). This should take you to the partitioning screen.
    On the Windows XP screen, this does not exist. Simply move on to the next step.


    c) Select the partition.
    Oh look, here are our partitions! Simply select the main partition (in this case, the 35 GB one), and hit Next. (On Windows XP, select the partition and hit ENTER.)


    If you want to make any further changes to the partition structure, click "Drive options (advanced)". (On Windows XP, you can delete the partition and add a new one instead with different options.)


    d) Relax... and finish the setup/installation of your main OS.
    Surprised? Don't be - you deserve a rest after you did you work in the first step!




    The Windows setup will automatically detect other Windows OSs on the system, and set up entries in the boot configuration to allow you to select your OS. Not bad, eh?

    3) Enjoy!
    Your dual boot is now ready to go! Hopefully you learned a bit from this tutorial, and enjoy your dual booting Windows system!

    Can't find your answer ? Ask !