Set The System's Boot Device Sequence

AMI-BIOS: For most versions, managing a PC's boot device sequence appears under the "Advanced BIOS Features" menu

If your PC has a relatively new motherboard, its BIOS will already include the functions necessary to support USB-attached boot media. If so, you need only make the right selections in that BIOS menu to boot from a USB flash drive. Older PCs, on the other hand, won't accept USB drives as valid boot devices. This means a BIOS update that supports USB boot options is necessary. You can find information about where to obtain such updates from your PC's (or motherboard's) user manual, on the driver CD included with the PC (or motherboard) or on the vendor's Website.

Normally, the hard disk precedes the USB flash drive (which falls under the heading of USB-HDD in most BIOS menus) in the boot order. If the hard disk contains a viable boot sector, the PC will start up automatically using the information it contains. Only when the hard disk suffers from a boot sector defect or an operating system can't be found will the PC boot from the USB flash drive instead.

Change this boot order. Plug the flash drive in, boot the computer and enter the BIOS setup utility. Normally, this means holding down the DEL or F2 key just as the computer powers up and begins the boot process. If you read the initial startup screen on your PC carefully, it will tell you exactly what you must do to access and alter your BIOS settings.

If your PC uses AMI-BIOS from American Megatrends, there are two possible ways to alter the boot device sequence. Each varies depending on the version of AMI-BIOS that's installed.

For the first variant, there is no menu entry named "Boot." Navigate to the sub-menu named "Advanced BIOS Features." Navigate to the item named "Boot Device Select... " and designate the USB flash drive as the first device in the "Boot Device Priority" list by selecting "1st" as its value. Then, hit the Esc key and set both the "Quick Boot" and "Full Screen LOGO Show" items to "Disabled" (this lets you see the BIOS messages during startup on the monitor). Exit the BIOS Setup utility using the "Save and Exit Setup" item in the main menu.

For the second variant, use the "Boot" menu to select the USB flash drive. It will show up under one of the following headings: "Hard Disk Drive", "Removable Device" or "Removable Storage Device. " Next, select the USB flash drive as "1st Drive" in the first position, then hit the Esc key. That device should appear in the menu named "Boot Device Priority" which might also show up as "Boot Sequence". Inside that menu, designate the USB flash drive as the "1st Boot Device", hit the Esc key and save all changes in the "Exit" menu by selecting "Exit and Save Changes".

The Phoenix BIOS that's so popular in notebook computers also lists the USB flash drive in its "Boot" menu (which might also appear as "Boot Device Priority"). In this case, the flash drive may show up as an entry in the "-HDD" or "-Removable Devices" sub-menu. Select the device class ("-Hard Drive" or "-HDD" for example) and use the F6 key to move the flash drive to the top of that list. Exit the BIOS Setup program by striking the F10 key, followed by the Enter key, to save all settings.

Expanding The Role Of USB Flash Drives

Flash drives aren't always recognized during the PC boot process. The USB flash drive controller and the PC's BIOS must be properly introduced to one another. That said, nearly all flash drives and PC can be configured so that the PC can boot from the flash drive.

You Need This: XP On The USB Pen Drive

In most cases, any compatible USB flash drive makes a suitable target for Windows XP installation. But the following system requirements must also be met:

• A USB flash drive with at least 256 MB of storage is enough for the uses described in this article. Additional system tools or applications require more space. The upper bound limits for storage in this case is 2 GB - a byproduct of the tool's use of FAT16 for the local file system.
• Most new motherboards recognize USB flash drives as valid boot media. But conventional motherboards that are more than two years old aren't likely to boot from a USB flash drive. But in many cases, this omission can be remedied through a BIOS update for that board.
• 1.5 GB of unused disk space is the maximum needed for the tool to do its job, particularly if you want to pre-install Service Pack 2 and RAM disk capabilities. 190 MB of unused space is all that's needed to use PE Builder and the applications described in this article, however. Additional plug-ins will increase storage requirements, as will additional tools or software.
• 512 MB of USB flash drive storage space is needed only if boot-up works from a RAM disk. Otherwise, 256 MB is big enough.
• Access to a USB 2.0 port is not mandatory, though booting with a USB 1.1 port takes about five times longer.
• A Windows XP Setup CD works fine as a foundation for PE Builder to generate the USB flash drive's contents.

Formatting The USB Flash Drive

Disk Storage Format Tool: This program from HP can format any USB flash drive

Most BIOS versions accept a USB flash drive as a boot disk only if it uses the FAT (File Allocation Table) file system. Before you can install Windows on the USB flash drive, it must first be formatted.

Warning! Windows XP also provides a tool to format USB flash drives, but the results of that process are error-prone. In a worst case situation, it can even destroy the flash RAM in a USB flash drive.

Installation requires the use of HP's freeware tool HP USB Disk Storage Format Tool instead. Once installed, you can run the program through this sequence of menu choices: Start, All Programs, HP Company. Select the USB flash drive you wish to format from the Device entry, then select FAT as the target file system for that device. Click Start to launch this process. Once complete, you must then copied the Windows XP boot files to the USB flash drive - namely,

%systemdrive%\boot.ini, %systemdrive%\ntldr, and %systemdrive%:\ntdetect (if you know the drive ID where these files live, use that instead - it's normally C). To make Windows Explorer display these files (they're ordinarily hidden), choose Folder Options... from the Tools menu, then click the View tab in the Folder Options window. Finally, in the Advanced Setting pick list, click the radio button underneath Hidden Files and folders that reads "Show hidden files and folders." Finally uncheck the box next to "Hide protected operating systems (Recommended)," so you can select and copy these all-important Windows XP files to the flash drive. The USB flash drive is now ready to boot your system. Next, you learn how to instruct your PC to boot from a USB flash drive.