can a charge off account be disputed if opened in 1999?

Depending on when the account first became delinquent, it will generally be reported to the bureaus for seven years from the first reported date of delinquency.

That being said, you can dispute anything that is on your credit reports. It is pretty much up to the creditor, whether they want to take the time to verify that they are reporting accurate information. Some companies have millions of accounts and so many disputes coming in, that they will just delete the account to save time. Other companies will actually take the time to investigate your dispute, and if their investigation shows you still owe them money, then they will leave it on your credit report.