A promissory note was written for an amount of money loaned in 1999. The debt has never been paid. What legal recourse do I have at this time, and what would the odds be of having the money re-paid?

Check your states, statue of limitations

If you have not passed the statue of limitation for collections, you can sue in court for a judgement

Can you tell us a bit more about the note. What payment date/time was specified if any? SOL may not apply depending on the payment date language. Otherwise everyone could just sit for 7 years and never pay. Back to you.