If the oil pump has gone, you would get the low oil pressure warning as suggested, but I also suspect that engine would only die after the light had been on for more than a few seconds, i.e. when something has got hot enough to sieze. Which fair comment at that point it's probably easier to swap the engine. But I'm also not convincied. I also suspect once cool, it would start again, even if it does run like a bag of spanners.
As other people have suggested, when you turn it over trying to start, does it turn over really fast, or make any strange noises?