You paid a collection in 2000 and it shows up in your credit report as last reported October 2004 is this legal?

It's nothing to do with "legal". They are simply a reporting agency. If you have proof, i.e, the statement of payment with the correct date, you simply send the reporting agency a certified copy of the letter and they will correct it. A recent statistic that I read was that over one third of all accounts at credit reporting agencies have errors in them. Please note that there are three credit reporting agencies. Once you fix that one, send to the other two to get them fixed as well. Then get a credit report (you are allowed one a year free from all three agencies) and verify that all three have done their job. Wait at least two months for this. Good luck.