While in the Air Force I was partying with some friends one night. We were all hammered drunk. A femail airmen and I were messing around sexually, but did not have any form of intercorse. She later told her friend it was not consentual afraid her boyfriend would find out, and leave her. Her friend contacted OSI and I was arrested and charged with Indecent Assault. After hearing of the trouble I was in she told OSI to drop the case and they did. I do not know exactly what she said to OSI, but never the less the case went no further, and I never went to court martial. However since there was alcohol involved, and I had a prior DUI I was administrativly discharged General under Honerable conditions. That was well over 5 years ago. I am now trying to obtain my P.O.S.T certificate for a Park Ranger job, and this comes back on my record. I can not obtain my P.O.S.T cert because I did not disclose this conviction (remember I was never convicted) How do I dispute this, and get it removed from my military/FBI record?

Which charge is showing up, the drinking part or the assault part.

Also for post, just the arrest will show up, even if not convicted

And to be honest with the drunken sex with a fellow worker, even with no charges, most likely the department would not consider you anyway,

My live scan Fingerprints came back saying I was denied because I answere no to any other convictions other than the DUI. It listed Indecent Assault from Langley AFB. I was under the impression if I was not convicted I didn't have to say yes.

She told OSI from the beginning there was no sex. My problem is getting far enough to explain the charges before they throw my app away. If I disclose that charge on my app I might be able to get my cert, but then the employers sees it as a conviction

You should have kept all documents. It does sound like you have a conviction - for the drinking and maybe some term regarding inappropriate behavior. You could see if a lawyer would think this can be appealed in any way, but I wouldn't count on it, sorry.