Norton/Symantec 12-30-1899 expiration date problem.

I am using Windows XP Pro updated with Service Pack 2 and Norton Internet Security 2005. A few weeks ago, the expiration date for the Norton sofware package suddenly changed to 12-30-1899 (in fact, my expiration date is 10-2005). My problem is that this prevents my Norton software from getting the latest info and protection from viruses, etc. I have been trying to work patiently with Norton's customer tech support website to correct this expiration date problem, but I am getting nowhere - primarily due to my lack of computer expertise. Has anyone else had this problem? If yes, did you solve it? If yes, can you explain to me how to solve it in computer jargon that is more basic than what is used on the Norton customer service website? Thanks for your help.