Hong Kong and American Law

If you committed a crime in a country and you got a criminal record in that country, then you have a criminal record. Whether HK has the same law does not matter. You still have to disclose your criminal record in Hong Kong. The only consolation is that the laws of HK are very comprehensive. So if HK does not have the same law, then it cannot be very serious and whoever you disclose your record to would understand that.
However, If by an American law you are allowed not to disclose your criminal record after satisfying certain conditions, then the same would apply in Hong Kong. ie. you do not have to disclose your record in HK. But I have to remind you that you are only allowed to do so if there is an American law governing this. In HK we call it the Rehabilitation of Offenders Ordinance.
However, as far as I know, in most expungement programs around the world your record is not deleted. A criminal record in most civilised countries is there forever. It will be kept on the files of the police forever. The law only allows you not to disclose it to other people in a legal way.
crime is something one has done that is against the law. criminal when used as a noun is the person who committed a crime. eg. he is a criminal. when used as an adjective it describes something that is a crime. eg. a criminal case / a criminal trial.

2007-11-22 18:12:48 補充：
If you have a criminal record, whether is has been expunged or not, you could not be employed by the HK gov. in the disciplined services such as police, immigration, correctional services etc. But they would consider you for clerical jobs or teachers.

it is a crime but not criminal, even in the U.S

That does not really consider a criminal record. For example, Speeding, drive 75 miles per hour in 45 miles per hour road is consider break the law. But this is not a criminal record.