Did you file the form
Have you moved since 1997
Any additional info you think is relevant
Generally the maximum time frame is 10 years, but it is possible that the statute of limitations is still open if the IRS has been unable to issue the assessment due to changes in address.
Because of the size of the assessment, it would be in your best interest to contact an attorney in your area that specializes in tax problems. They can assist you in determining whether the statute is still open, the proper amount, etc. With the proper counsel and the right situation penalties and sometimes interest are negotiable. There is also the possibility of an offer in compromise if you are unable to pay the full amount over time.
Hope this helps.
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