Help-PGP Desktop keys invalid

Hi can someone help me? Ive been emailing back and forth with Symantec with case # 06809670 and they directed me here.  My hard drive crashed while I had PGP desktop installed on it and I installed it on a different laptop and now when I try to decrypt something, it says: IT IS NOT POSSIBLE TO DECRYPT MESSAGE BECAUSE YOUR KEYRING DOES NOT CONTAIN USABLE PRIVATE KEYS THAT CORRESPOND WITH ANY OF THE ABOVE PUBLIC KEYS.  

HELP!!!!!!!!!