The Windows Learning Center

Windows Boot (Startup) Disks and USB Keys

Be prepared for startup and other computer problems. Learn how to prepare an emergency boot medium on CD/DVD disks or USB keys with system repair and anti-virus features. Learn about the differing kinds of boot systems.

Most people probably do not pay a lot of attention to the process called “booting” that goes on when they first turn on their computer. However, there may come a time when it is necessary to get involved in the boot process in order to remedy some problem and to make use of something called a boot disk (or as Microsoft has sometimes called it, a “startup” disk). Or, If you are set up for it, it may be a USB key. You may go through life without ever having to use one, but like a spare tire for a car, an external boot medium is something everyone should have. There are various versions of boot disk or USB systems possible, but the basic contents are some form of operating system that will allow you to run your computer from somewhere other than the hard drive.

The Boot Process

When you turn on your computer, it has to go through a whole series of steps before it ever gets around to loading your programs; it has to “pull itself up by its own bootstraps” (the origin of the term “boot”). Before the central processing unit (CPU) can access the keyboard, monitor, hard drive, or other basic components, the CPU has to get instructions from a small amount of permanently stored code called the BIOS (Basic Input/Output System). After the CPU has been instructed on how to get things in and out, the BIOS then tells the computer where to look for its next set of instructions.

Once upon a time the computer would first look in the A: drive and if nothing was there it would then look on the C: drive. (Just about everybody of a certain age has probably gotten one of those “Non-system Disk” messages when they forgot and left a diskette in the A: drive). Nowadays, the BIOS is usually set up so that the CD drive and /or a USB port is included in the boot sequence. The sequence may be first the CD drive, then the USB port, and finally the C: drive or may be some other permutation of the order of the drives, depending on your system. Thus there is an option to run the computer from somewhere other than the C: drive in case that becomes necessary or desirable.

An example of such a situation is when you sit down at your computer, turn it on, the BIOS does its thing and then nothing more happens. Or perhaps you get some messages on a black-and-white screen to the effect that Windows is on strike and will not load. What now? Assuming that you have previously done all the steps that are supposed to be part of routine maintenance, you may have a bad hard drive or perhaps a Registry that has gotten corrupted. If the hard drive is totally dead, a boot disk won't do much good until you get a new hard drive, but if the problem is something awry in Windows, then a boot disk or USB device may very well allow you to repair the problem.

Special situation with Windows 8.x

With Windows 8 you may encounter a new boot process that makes standard boot disks unusable. If the BIOS has been replaced by UEFI, most boot disks made for previous Windows systems will not work. See this Microsoft article for more information about the new process.

Windows full installation disks used for system repair

If you have a full bootable Windows installation disk, then that may allow you to repair the problem. A Windows XP full installation disk contains the Recovery Console , which may allow you to to deal with problems. Windows Vista/7 full installation disks provide even easier ways to deal with a corrupted system.

It is rare for a full installation disk to be provided these days but you can download free legitimate Windows 7 disks from Microsoft's online service at DigitalRiver.

It is rare for a full installation disk to be provided these days but you can download free legitimate Windows 7 disks from Microsoft's online service at DigitalRiver. Here are the links:

Update, March 41, 2014. Microsoft has been playing games with the Digital River downloads. Sometimes they are up and sometimes they get disabled.

Boot or Rescue Disks

Unfortunately, it is now general practice for major vendors to provide only a recovery disk or just a recovery partition when you purchase a PC. These recovery or restore media only serve to restore the system to the way it was when it left the factory. So most PC users will need to prepare some sort of rescue disk to be kept for use in emergencies. The term "boot disk" can have several meanings. Personally, what I want is a disk that can read and write to the hard drive and that contains some tools that will help repair problems and deal with malware.

Here are a number of ways to create or obtain a bootable medium to repair a system that won't boot the normal way.

Anti-virus boot CDs

Most popular anti-virus programs provide for the creation of a bootable CD to run the anti-virus program. These can be indispensable when malware has made your PC unbootable. Consult the instructions for your anti-virus program and be sure to create an anti-virus boot CD. There are also some free CDs available for download. Here are three:

Disks containing the Windows XP Recovery Console

Microsoft provides software for creating a set of six diskettes for reinstalling Windows XP for those with no bootable CD.The details are here. It doesn't seem to be widely known but these disks also contain the Recovery Console. Thus creating this set of diskettes will give those without a Windows CD (but with a floppy drive) the option of using the Recovery Console. It is tedious; you have to wait while the system slogs through the setup process and loads all six disks but if it saves your system it will be worth it.

How to create a CD containing the Windows XP Recovery Console

If you have neither a Windows XP CD nor a floppy drive, there is a method for placing the floppy disk contents on a bootable CD written by Dean Adams. He has created a nice package that allows for the creation of a bootable CD. He has made the creation as easy as possible for the user with a batch file that does all the work.. His package includes all the software needed (except the Microsoft software mentioned above) and detailed instructions. Download the package here.

Boot disk for Windows Vista

Microsoft has a free download called Windows PE that allows you to make a bootable CD. Here is Microsoft's description:

Windows Preinstallation Environment (Windows PE) 2.0 is a minimal Win32 operating system with limited services, built on the Windows Vista kernel. It is used to prepare a computer for Windows installation, to copy disk images from a network file server, and to initiate Windows Setup.

It provides read/write access to NTFS file systems, 32- and 64-bit hardware drivers, and network connectivity.

Boot and system repair disk for Windows 7

In Windows 7, Microsoft has finally provided an easy way to create a disk for booting and repairing a system that won't start or has corrupt files. Creating a system repair disk is described on another page. All users of Windows 7 should create one of these.

Complete Linux systems on a bootable CD

There are many varieties of Linux live disks available. These are actually entire independent Linux systems with much software, all on one CD and can include many system repair tools. One example is the Knoppix CD. Another is Puppy Linux. There are also other Linux distros such as Ubuntu that can be run on a single CD.

Bootable CDs with diagnostic and repair tools

There are a number of specialty CDs available that come with assortments of repair and diagnostic tools. Here is a selection:

Booting from a USB flash drive

Provided that your BIOS recognizes booting from USB, you may be able to boot from one of those handy flash memory devices known by various names but often called a "thumb drive". There are a variety of approaches and several are given below.

Create a bootable USB flash drive

First, you will need to create a bootable USB key. If you have Windows Vista or Windows 7, this is easy to do from the command line as described here. Otherwise, you can try a free utility described at this link.

Create a bootable USB key with Linux installed

As discussed above, many Linux distros can be run from a bootable CD but there are advantages to using a USB flash drive. For one thing, it is faster. One way to create a bootable USB drive with your favorite Linux distro installed on it is described at this link. Another approach for is to create a bootable USB key and add a Linux image to it as described at this link.