* Proper Noun: When referring to the mythical figure from Greek mythology, it's a proper noun.
* Common Noun: If used to refer to something or someone viewed as a source of troubles or evils, it becomes a common noun.
* Adjective: In some cases, "Pandora" can be used as an adjective, like "Pandora's box" to describe something that contains potential trouble.
So, the answer is it depends on the context.