WINDOW XP -USB PORTS NOT RECOGNISING NEW HARDWARE

DEAR CYBER FRIENDS,
I AM HAVING A PECULIAR PROBLEM OF MY WINDOW XP IS NOT RECONGNISNG THE HARDWARES CONNECTED TO USB PORTS. I HAVE CHECKED THE WORKING OF USB PORTS AND IT SAYS THAT THEY ARE WORKING PROPERLY. FOR THE NEW HARDWARE I HAVE EVEN LOADED THE DRIVER SEPERATLY. STILL IT DOESN'T RECOGNISE. BUT THE DEVICE IS GETTING THE POWER FROM USB PORTS. IF ANY BODY HAS RESOLVED SUCH PROBLEM PL SEND ME SOLN.IF ANY BODY HAS SUGGESTION PL SNED ME. WITH THANKS & REGARDS