Plug and play devices are hardware and software designed such that they are automatically recognized by the operating system. In order for Windows XP to fully support plug and play devices, the computer should have a BIOS that supports ACPI or Advanced Configuration and Power Interface. ACPI allows the computer's motherboard and operating system to control power needs and modes of operation of various devices. The key to a successful plug and play device installation includes the following:
• Possessing the most up-to-date device driver
• Follow the directions provided by the device manufacturer

Install the device according to the device manufacturer's instructions. Once installed, switch on the computer. The Windows XP Found New Hardware wizard appears. Windows XP attempts to find a driver for the new device. Plug and play devices make use of a special .CAB (cabinet) file called DRIVER.CAB located in %winroot% \ Driver Cache \ i386 folder (where %winroot% is normally C: \ WINNT or C: \ WINDOWS). This file is almost 75 MB and contains more than 2,500 compressed files. If Windows XP detects new hardware, it will automatically search DRIVER. CAB for a driver. If a driver cannot be found, a dialog box appears. The best policy with any operating system is to use the latest driver even if the operating system detects the device. An exercise at the end of the chapter outlines how to install a new hardware driver.