The boot disk (disk to start the computer) will help restore and repair the computer if a major error occurs, or a virus renders your computer unusable or unable to start the system. Learn how to create a backup boot disk for your computer, both Windows and Mac.
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Method 1 of 3: Creating a Boot Disk for Windows 8

Step 1. On a Windows 8 device, swipe in from the right edge of the screen
If you are using a mouse, point to the lower right corner of the screen

Step 2. Tap or click Start

Step 3. Type "Recovery" into the search field
A panel containing the search results will appear on the screen.

Step 4. Click Settings and select Create a recovery drive

Step 5. Put a check mark next to Copy the recovery partition from the PC to the recovery drive

Step 6. Click Next
The screen will then tell you how much data capacity is required to create a boot disk.

Step 7. Make sure that the capacity on your flash disk (flat disk) or blank CD is sufficient to create a boot disk
Data capacity will vary depending on the type of Windows 8 device you are using. For example, if your device requires a 6 GB capacity boot disk, you will need a flash disk with at least 6 GB of free space.

Step 8. Insert the flash drive into one of the empty USB ports (ports) on the Windows 8 device
If you are using a blank CD or DVD, select Create a system-repair disc with a CD or DVD from the drop-down menu before inserting the CD into the device

Step 9. Follow the next instructions prompted by Windows 8 to complete the boot disk
Once completed, the boot disk can be used to restore or repair Windows 8 in case there is a problem with the device starting the system at any time.
Method 2 of 3: Creating a Boot Disk for Windows 7/Vista

Step 1. Click the Start button of your Windows 7 or Windows Vista computer

Step 2. Select Control Panel

Step 3. Click System and Maintenance, then select Backup and Restore

Step 4. Click Create a system repair disc in the left pane of the Backup and Restore window

Step 5. Insert a blank CD into the computer

Step 6. Select the name of the drive (drive) used from the drop-down menu next to Drive

Step 7. Click Create disc
Windows will start writing the files needed to repair the system to the disc you inserted.

Step 8. Click Close after Windows notifies you that the boot disk has been created
The boot disk can now be used if you later have trouble starting your Windows 7 or Windows Vista system.
Method 3 of 3: Creating a Boot Disk for Mac OS X

Step 1. Open the "Applications" directory on the Mac

Step 2. Open the Mac App Store app

Step 3. Find and download the latest OS X installer from the App Store
As of this writing, OS X Mavericks 10.9 is the latest installer provided by Apple.
If you want to use an earlier version of OS X that was previously purchased from the App Store, hold down the "Option" key and click Purchases in the App Store to access and re-download the OS X installer

Step 4. Insert the flash drive into the USB port on the computer
The flash drive must have at least 8 GB of free space.

Step 5. Go to the "Applications" directory and click on Utilities

Step 6. Select "Disk Utility"
Your computer will start collecting information from the flash drive you inserted.

Step 7. Click the USB flash disk once it appears on the left of "Disk Utility"

Step 8. Click the tab labeled Partition in "Disk Utility"

Step 9. Select 1 Partition from the drop-down menu under Partition Layout

Step 10. Select Mac OS Extended (Journaled) from the drop-down menu next to Format

Step 11. Click the Options button at the bottom of the "Disk Utility" window

Step 12. Select GUID Partition Table and click OK

Step 13. Open Terminal from within Utilities in the "Applications" directory

Step 14. Type the following command into Terminal:
"defaults write com.apple. Finder AppleShowAllFiles TRUE;\killall Finder;\say Files Revealed".

Step 15. Press the Return key on the keyboard to execute the command
The Mac will then begin formatting the flash drive to create a Mac OS X installer program.

Step 16. Go to the "Applications" directory, then look for the installer program that was downloaded from the App Store
For example, if you download OS X Mavericks, the installer program is called "Install Mac OS X Mavericks.app".

Step 17. Right-click on the installer and select Show Package Contents from the list of available options

Step 18. Click Contents and select Shared Support in the packaged content window

Step 19. Double click the InstallESD icon. dmg
An icon that says "OS X Install ESD" will appear on the desktop.

Step 20. Double click the OS X Install ESD icon
The directory will open to reveal a series of hidden files, including "BaseSystem.dmg".

Step 21. Return to the "Disk Utility" application, then click the name of your flash drive on the left

Step 22. Click the tab labeled Restore in "Disk Utility"

Step 23. Click and drag the hidden files entitled "BaseSystem
dmg to the Source column in "Disk Utility".

Step 24. Click and drag the new partition from under your flash drive name on the left pane to the Destination column
Generally this new partition will be labeled "Untitled".

Step 25. Click the Restore button in Disk Utility

Step 26. Click Erase when prompted to confirm that you want to replace the contents of the flash drive

Step 27. Wait for the Mac to create a boot disk on the flash drive
Generally this process will take up to 1 hour to complete.

Step 28. Click System in the left pane and select Installation after the Mac has finished copying the files to the flash drive

Step 29. Delete the directory file labeled Packages

Step 30. Go back to the loaded directory named Install ESD. dmg on the desktop

Step 31. Copy the directory named Packages

Step 32. Go back to the installation directory and paste the Packages directory
This new directory will replace the previously deleted directory files.

Step 33. Eject the flash drive from the computer
Your flash drive can now be used as a boot disk in case you need to reinstall or restore the current version of Mac OS X.