Boot From Emergency Disks

Booting a troubled computer and fixing common startup problems is a breeze when you have a bootable diskette handy. Simply insert the diskette in its drive and start (or restart) your computer. The BIOS will spring into action, retrieve the system files from the bootable diskette, and launch either DOS or Windows. How you proceed depends on which bootable diskette you use. See the article "Create Emergency Boot Disks" for more on creating such disks.

If you use the Win98/Me startup disk. When starting your PC with a Windows 98 or Windows Me startup disk, your system presents you with several startup choices, including the Start Computer With CD-ROM Support and Start Computer Without CD-ROM Support options. We suggest selecting the first option because it lets you access content from the Windows installation CD-ROM. After making your selection, the A:\> command prompt will appear on-screen.

What good is a DOS command prompt to the average Windows user? A lot, as long as you know the right commands to use. The following list of commands can help you start your journey on the road to recovery.

CD—You can use the CD (Change Directory) command to navigate the contents of your storage drives. Simply type cd at the command prompt, type the name of the folder you want to access, and press ENTER. To access the Windows and System folders on the C: drive, for instance, you would type cd c:\windows\system at the command prompt.

COPY—The COPY command helps you copy files from one location to another. To use the command, type copy at the command prompt, followed by the name and location of the file you want to copy and the location of the folder where you want to store the new copy. To copy the Disk Defragmenter utility from the Windows drive to a diskette, for instance, you might type copy c:\windows\defrag.exe a: at the command prompt and press ENTER.

DIR /P—Use the DIR command to view the contents of the current drive or folder. The /P switch lets you view the contents one screen at a time.

FDISK—The FDISK utility helps you divide a storage drive into several partitions (or storage device areas treated as separate storage units, each with its own drive letter). You can activate the FDISK utility by typing fdisk at the command prompt and pressing ENTER. Follow the on-screen instructions to complete the partitioning process (although there are some things you need to consider, such as backing up all your hard drive's data onto removable storage media, before proceeding).

FORMAT—When a drive's data is damaged beyond any hope of recovery, you can use the FORMAT command to delete all of it and start over. To do this, type the command followed by the letter of the drive you want to clean out. To format our Windows drive, for instance, we would type format c: and press ENTER. Use this command with caution, however. There is no cheap or easy way of recovering content from a drive after you format it.

SCANDISK—Like its Windows counterpart of the same name, the SCANDISK utility in DOS scours a storage drive for errors that lead to data corruption. You can access the utility by typing scandisk at the command prompt and pressing ENTER. Follow the on-screen instructions to proceed.

SYS—This simple command writes a new set of system files to the Windows drive, thereby fixing any startup problem that stems from a corrupt system file. All you have to do is insert the startup disk in the diskette drive, type sys c: at the command prompt, and press ENTER.

If you use Windows XP's MS-DOS startup disk. Like the Win98 and WinMe startup disks, WinXP's MS-DOS startup disk boots the computer to an A:\> command prompt. Unfortunately, that's where the similarities end. The MS-DOS startup disk lacks most of the best DOS troubleshooting tools, including the FDISK and SCANDISK utilities. Because of its limited capabilities, we find the MS-DOS startup disk to be of little assistance in troubleshooting startup problems. Consider using the WinXP Recovery Console instead.

For more information about using WinXP's Recovery Console, visit Microsoft Product Support Services (support.microsoft.com), type 307654 in the Search The Knowledge Base field, and press ENTER. When the results of your search appear, click the How To Install And Use The Recovery Console In Windows XP link.

If you use WinXP's Windows boot disk. When you boot your computer using the Windows boot disk, WinXP should start as it normally does. Your optical drive will work, and you will have access to all of WinXP's built-in troubleshooting and maintenance tools.

If your PC runs Windows Vista. You can use Vista's installation DVD to launch the Startup Repair wizard, which fixes problems that prevent Windows from starting up.

If your PC doesn't already give you the option to boot from an optical disc (a CD or DVD), you'll need to configure the BIOS (Basic Input/Output System; a basic OS that runs alongside Windows) to provide this option during startup.

To configure the BIOS, restart your PC and press the key that starts the BIOS shortly after the PC starts. (In most cases, the DELETE key initializes the BIOS). When the BIOS menu appears, use the Arrow keys to navigate the submenus. Look for the Boot Order (or similarly titled) section. This section determines the order in which the computer searches its devices (such as the floppy drives, hard drives, or optical drives) for an operating system.

Use the arrow keys to move CD-ROM to the top of the of list (the #1 position) so the computer will check the CD or DVD drive first. Next, press the F10 key (if you have a Microsoft keyboard, you may need to press the F LOCK key on the right side of the FUNCTION keys to enable the F10 key). If a window prompts you to accept the changes, accept them and then press the ENTER key. The computer will reboot.

As the computer starts, watch the screen for a Press Any Key To Book From CD message, which will likely appear at the bottom of the screen (it displays only briefly; if you see the Windows logo, you missed the message and you'll need to restart the computer to try again).

At this point, the Windows Boot Manager screen may appear. If it does, choose Windows Setup and then press ENTER. A Windows Is Loading Files message will appear briefly and then the Install Windows window will appear. This windows displays the OS's default language. Click the Next button. At this point, you'll see a large Install Now button. Rather than reinstalling Windows, click the Repair Your Computer link near the bottom of this window.

When the System Recovery Options window appears, select Microsoft Windows Vista from the list (chances are, it's the only item that appears in the list) and then click the Next button.

The next window displays several problem-solving options. Click the Startup Repair option and then wait while the tool searches for and fixes any damage to your computer's startup process. Click Finish when the Wizard completes. At this point, your PC should be able to boot Windows without incident.

by Jeff Dodd