I have been trying to figure out the name of a movie that came out sometime between the early 90's to mid 2000's. I distinctly remember there being a small pandora's box type cube. I think it was found in an archaeological dig site and may have even been on another planet or involved aliens. Obviously something bad happened afterwards. I'm not sure that I even ever saw the movie. I definitely remember seeing the preview and the narrator mentioning something about bad things happening because they unknowingly opened pandora's box. I realize this is a vague description and I may have some details wrong because my memory from this period of time is damaged.
Are you thinking of Hellraiser IV: Bloodline?
It involves the Lament Configuration (a small cube); the Cenobites (demons which could be mistaken for alien); part of it takes place on a space station; and it's Hellraiser so it's very gloom-and-doom.
IIRC, this may have been the full trailer for Alone in the Dark (2005), starring Christian Slater and Tara Reid. The movie was universally panned, but honestly it wasn't THAT bad in my opinon.
The film has almost no connection to the game series of the same name, but instead revolves around the accidental opening of a portal which allows demonic shadow-like creatures onto Earth from another dimension. I am unable to find the full trailer while at work, but will try to get it added this evening.
The movie involves much of what you described, with numerous scenes taking place in a museum and ancient artifacts being central to the plot. The demonic creatures of the film look very similar in design to the Xenomorphs of the Alien franchise, and one of the ancient artifacts is cube-like in shape (actually, it's more like a hexagon I think). At one point during the film, the protagonists are fighting one of the demons while in the museum or its warehouse, and use whatever they can - including ancient weapons - to fend off the creature.
UPDATE: I was unable to find the full trailer on YouTube, but it turned out I had a copy of it from way back in 2005 when the movie originally came out (and my wife says my hoarding isn't good for anything... HA). I uploaded the trailer to YouTube and here it is:
Narration Guy: Some gateways... should never be opened. Some fears... should never be seen. And some terrors... can never be stopped.