How to reset password to access IT dept. website?

I COULD NOT LOGIN TO FILE E-RETURN. IT IS SHOWING INCURRECT USER ID. BUT LAST YEAR I HAVE FILED MY        E-RETURN [AY 2011-12]. BY CLICKING 'FORGOT PASSWORD?' LINK ON THAT PAGE, IT IS ASKING FOR PAN NUMBER. I HAVE GIVEN THE SAME. BUT STILL IT IS SHOWING ' USER DOES NOT EXISTS' MESSAGE. CAN SOMEONE HELP ME HOW TO CHANGE MY UNAME AND PASSWORD TO FILE MY E-RETURN FOR THIS AY.