Windows XP Professional and Windows 2000 or NT

Installing both Windows XP and earlier NT versions on the same system is also something you might want to do. This configuration is popular for many people already running Windows NT 4.0 who want to try Windows XP before completely canning their previous installation. This is a worthwhile pursuit and can be obtained with a little care and planning.

If you already have Windows NT 4.0 installed, you are probably using either the FAT16 file system or NTFS. Looking at Table 31.1, you can see that Windows XP supports both of the file systems supported by Windows NT 4.0. When installing Windows XP Professional, you simply select a new installation, as opposed to an upgrade, and the installer will handle the rest. As with the previous configuration, Windows XP will save your Windows NT 4.0 installation and give you the choice of selecting it at boot time.

This setup also can suffer from the same sort of problems as the Windows 98/Windows XP configuration. You must be careful to not overlap your new and old installation directories. And although you can have them coexist on the same partition, you'd be installing files from two different versions of Windows into the same "Program Files" folder. It's much more prudent to have them occupy separate partitions or drives.

CAUTION

Windows XP uses an updated version of the NTFS file system: NTFS5. Before installing Windows XP, you must be sure that you've first updated your installed version of Windows NT 4.0 with service pack 4 or greater. This will ensure that your NT 4.0 installation will be capable of reading your NTFS disk after adding Windows XP to your system. Service pack 6a is the current (and final) version.

Even with the service pack, however, NT Version 4 won't be able to read XP's encrypted or compressed files.

If you want to test or use Windows XP's advanced file system features, or if the NTFS version issue worries you, you can use this setup on a dual Windows XP/Windows NT installation.

Partition 1	Windows NT, NTFS version 4
Partition 2	Windows XP, NFTS version 5
Partition 3	Shared files, FAT16

Because Windows NT can't read FAT32 disks, you have to use a FAT16 partition as a shared file volume.

To dual-boot NT and XP, do the following:

1.	Install Windows NT 4.0. Chances are good that you already have it installed, in which case this portion of the job is already complete.
2.	You're going to want to have another partition to house Windows XP. Unless you have free, unpartitioned space available, you'll need to install an additional disk drive, or use PartitionMagic to insert a new partition on an existing drive. If you do have unpartitioned space, you can install Windows XP directly into that. You can leave the new partition unformatted.
3.	Boot up Windows NT, insert the Windows XP setup disc, and choose Install Windows XP from the menu. (If the menu doesn't start automatically, look on the CD's root directory for Setup.exe and run it.)
4.	Choose New Installation from the wizard's first page; otherwise, you'll wipe out Windows NT 4.0.
5.	Accept the agreement, enter the serial number, and follow the wizard.
6.	From the Select Special Options page of the Windows XP Setup Wizard, select the Advanced Options button. Check I Want to Choose the Install Drive Letter and Partition During Setup, and then click OK.
7.	After the Windows Setup Wizard copies some files to your hard disk, it will reboot your system and continue the installation from a text-based setup. From this setup, you will have the option to select where you'd like to install Windows XP. Choose the partition you created in step 2, or choose any unformatted free space (if you have any).
8.	Next, you will be given the option to select how you want the target partition formatted. Select Format as NTFS or Convert to NTFS.
9.	The Setup process will continue normally. When it's finished, you'll be able to choose either Windows NT 4.0 or Windows XP when your computer boots up.

TIP

See the earlier section titled "Formatting the Data-Sharing Partition" for some thoughts about creating a third partition to store data that can be shared between the two operating systems.