Beginners Guides: Dual OS Installation of WindowsXP 32-bit/64-bit

The era of 64-bit Windows is almost upon us, now that both Intel and AMD have fully integrated 64-bit capabilities into their mainstream processor lines. Windows XP x64 Edition has been out for several months now, but its capabilities remain largely untapped by software. This fact is likely to change dramatically in the next six months or so as the emphasis moves more towards 64-bit.

The trouble is though, Windows XP x64 Edition does not play nicely with much 32-bit software, and requires new drivers for all your existing hardware, which may not yet (or ever) be available. You may want to move to the 64-bit OS to take advantage of your shiny new processor's capabilities, but what happens if half your games don't work and the other half run slower due to driver issues? The major videocard companies are admittedly close to perfecting their 64-bit drivers, but 'close' could mean anywhere from 3 months to a year before they are at the same level of performance as their 32-bit siblings.

To most people, the logical answer is to install Windows XP x64 Edition while still keeping XP 32-bit intact on the system. This allows you to mix and match the two operating systems, avoiding software failure and discovering which is best for each application and game. While this is a bit of a drain on hard drive space, it's more than worth it in terms of frustration avoided. It's also easy to do, and in this short guide, PCSTATS is going to show you how to go about creating your 64-bit/32-bit XP dual installation.

How dual-booting Windows XP works

Here's the rundown on multiple Windows installations: Windows XP uses the BOOT.INI file to identify which versions of Windows reside on which disk partitions on the system. BOOT.INI (as well as the NTLDR and NTDETECT files) must always be present on the first bootable partition (the primary partition of whichever hard disk the BIOS attempts to boot from first), usually the C:\ drive. The actual files and directories that make up each Windows operating system can be located on any drive or partition as long as an entry for them exists in the BOOT.INI file.

As long as each new Windows operating system you add can create or make changes to BOOT.ini, the NTLDR file which actually starts the Windows XP boot process will know where the system files for each OS are located, allowing those operating systems to load. Because of this, it's important to add operating systems onto your system by order of date when you are creating a dual-boot. Older operating systems should be installed before later ones, because earlier versions of NTLDR may not be able to accommodate the needs of later Windows operating systems. Pre-Win2k, NTLDR was not used at all.

This system makes multiple installs of any recent Microsoft operating system extremely easy, provided you do not mess with the files on the original partition. The boot loader for XP will happily accommodate pointers to any number of Microsoft operating systems on different drives and partitions, giving you a choice each time you start your computer.

In order for this guide to work, we've got to make a couple of assumptions: number one, that you have a 64-bit capable processor (either AMD Athlon 64, Opteron or EMT-64 enabled Intel Pentium 4/D/EE) and a working 32-bit installation of Windows XP (though in practice, Windows 2000 or 98 will work just fine too), and number two, that you have a free partition on one of your physical hard drives which you can use to host the operating system files for the 64-bit version of Windows XP.

If the computers processor is not 64-bit compatible, you will not be able to install WindowsXP x64 Edition.

You'll also need to download and install the Windows XP x64 Edition trial version and burn it onto CD, or purchase the full operating system.