I recently encountered an issue while trying to connect my android device to my laptop running XP.  Firstly, the installation process did not resemble the instructions as documented here (http://developer.android.com/guide/developing/device.html#XPFreshInstall) in that the new hardware wizard did not automatically kick-in.  Furthermore, it was difficult to know which was the correct target USB driver to update when viewing the Device Manager dialogue.

The solution:
Keep the Device manager open while removing and then reconnecting the android device to your pc/laptop. You should be able to visually see which new USB entry has just appeared in the Device Manager. Then you can update the driver as per the installation instructions.

Once you have successfully installed the device driver, you can test by opening a dos prompt to the <android_sdk>/tools directory and then running the command ‘adb devices’.  If this does not show the new device, try running the command ‘adb kill-server’.  You can then rerun the ‘adb devices’ command to restart the server and list the (hopefully!) updated list of devices!