Verify Compatibility

• Most USB devices and USB ports meet a standard called USB 2.0. Occasionally, however, you may encounter a computer that does not have USB 2.0 compliant USB ports. Verify that the computer on which you are attempting to use the USB device is USB 2.0 compliant. This can easily be found in your user documentation, or at the computer manufacturer's website. If you have a USB 2.0 compliant device, but the computer's USB ports are not, there is a high probability that the problem cannot be fixed without purchasing additional hardware. If using a laptop, a PMCIA CardBus USB 2.0 adapter can be installed. A PCI USB 2.0 cards can be installed in desktops to add USB 2.0 compatibility.
  
  

Power Consumption

• Verify that the USB device giving you problems does not require an external power source. Many USB devices, such as larger external hard drives, require an external power cable to be plugged into the electric socket. When these devices are plugged into a USB port without the proper amount of power, they can be unrecognized, installed improperly or malfunction.
  
  

Test the USB Ports

• To test the functionality of the USB port, try inserting another device into the port. If it is recognized, then the port is working. However, there are cases where some USB ports receive more power from the motherboard, especially during bootup. Restart your computer, then try the malfunctioning device in another USB port after Windows XP has fully booted.
  
  

Check the Device Manager

• The Windows XP device manager is a tool that allows you to quickly locate hardware issues on your system. When there is an unrecognized piece of hardware or an improper driver being used, they can be quickly located from the Device Manager. To access the Device Manager, right-click on "My Computer," then select "Properties." Next, select the "Hardware" tab and click "Device Manager." Look for a yellow "!" or red "X" next to any entries in the device manager. If you see a problem entry with either USB or Universal Serial Bus in the title, then try reinstalling the software that came with the device displaying the problem.
  
  

Universal Serial Bus Drivers

• If none of the previous steps have fixed your problem, your USB drivers may be the issue. To remove these drivers, go back to the Device Manager. Double-click on the "Universal Serial Bus controllers" heading, which will then expand. Right-click on each individual entry under the "Universal Serial Bus controllers" heading and click "Uninstall" to remove each one. Restart your computer and reinstall the USB drivers to correct any driver related issues.