Are you running version 2.7.2 and Virtual Box ?
So it goes to a black screen or crashes what happens exactly?
There are problems with certain model Macs I suggest you try using the test build of VirtualBox here: https://www.virtualbox.org/wiki/Testbuilds
I gave you my suggestion.
Ok it simply has problems with some macs you might try running Linux on that Mac. I'll opt out.