Are any devices malfunctioning? Select Start, All Programs, Accessories, System Tools, System Information. Open Components under System Summary and click on Problem Devices. Is anything listed there?
Are there any yellow question marks in Device Manager? Right click on the My Computer icon on your Desktop and select Properties, Hardware, and Device Manager. If yes what is the Device Error code?
To see Hidden Devices (Non Plug and Play Drivers) you need to select View, Show Hidden Devices. It is necessary to do this every time you open Device Manager if you need to see them.
A further complication can be Ghosted Devices –installed but not connected!
http://www.lockergnome.com/windows/2005/04/29/display-hidden-devices-in-device-manager-xp/
Hope this helps, Gerry Cornell