Any time you add or remove hardware from your PC, you open the door to all kinds of trouble. Long waits while Windows adjusts its settings, IRQ conflicts, and outright crashes are common occurrences, notwithstanding Plug and Play technology's promise to make life easier. But at least Windows' hardware profiles simplify changing your system's hardware.

A hardware profile is a list Windows generates to help it quickly set up your computer's hardware each time the OS starts. On start-up, Windows looks for the hardware profile that was last used, compares it to the current hardware configuration, and (if the two match) launches with that profile. Notebook users frequently use hardware profiles immediately after they add or remove pointing devices, keyboards, and other computing accessories.

If the hardware profile doesn't match your system's configuration ù for instance, when you've just slipped your notebook into a new docking station equipped with a DVD-ROM drive or an Ethernet card ù Windows looks for an existing hardware profile that does match. If it can't find one, Windows creates a new profile by identifying and installing each new device. This takes a while.

You can avoid the time-consuming identification process by keeping extra profiles on hand. Sometimes you have to create these yourself, but not always. With a perfect Plug and Play system (Windows 98 comes close to this) there's no need for hardware profiles ù the system will automatically recognise and configure everything. And if you have a notebook and docking station with a Plug and Play BIOS that works flawlessly, Windows will automatically generate and load a second profile. Plus, you may even be able to hot-dock your system ù that is, add hardware components to it while it's running, without having to reboot.

But many systems do not fully support Plug and Play. If that sounds like your system, you'll have to manually create a second hardware profile.

Caption: Create new system hardware profiles as your
computer's configuration changes

Caption: After you've disabled a device in Device Manager,
a red X appears over its icon

Caption: You can disable hardware in selected profiles for quicker boot-ups

Start up your PC in its original hardware configuration ù without any peripherals. Then right-click the My Computer icon on your desktop, select Properties, and choose the Hardware Profiles tab. Your current hardware profile ù which is most likely named "Original Configuration"ù should be listed in the centre box along with any other hardware profiles for your computer.

To create a new profile, you need to make a copy of the Original Configuration profile. Do this by clicking the Copy button at the lower left of the dialogue box. A second dialogue box will appear, allowing you to enter the name of your new profile. We'll call ours External DVD Configuration, but you can use any name that distinguishes this profile from others you already have.

Once you've created External DVD Configuration, you need to customise it as your alternative hardware configuration. To do that, you'll have to restart your PC. Windows will prompt you during start-up to choose a profile. Select External DVD Configuration. Now connect the new hardware ù in this case, the external DVD-ROM drive. Windows should detect the new hardware automatically. To make sure it has found and registered your new device, run the Add New Hardware wizard from Control Panel. Since External DVD Configuration is now the active hardware profile, any new device you add to your PC will be registered in that profile.

You can also remove devices from a profile if you no longer want them to appear in it. Right-click My Computer, click the Device Manager tab, and double-click the device you want to remove. In the Device usage section at the bottom of the General tab, place a check in the Disable in this hardware profile box. A red X over a device's icon in Device Manager indicates that it's disabled.

Disabling a device is also a handy way to diagnose hardware problems. Suppose you suspect the network card in your desktop PC ù or its driver ù is conflicting with some other part of your computer and causing intermittent system crashes. Instead of removing the network card and uninstalling its drivers, try disabling the card and see if the problem persists. If it does, simply re-enable the card and focus your attention elsewhere.

Hardware profiles also provide you with an effective, hassle-free way of testing whether or not new components are compatible with your system. By installing the new internal or external device into a second hardware profile, you can use it for however long you want while waiting for bugs or conflicts to surface. If you experience no such problems, you can return to your original hardware configuration and solve the problem at your own pace. And if no problems arise, you can simply delete your original profile; Windows will then automatically use the new one.