Look, usually I'd ask for the log file now, but since blackbox is completely stable and absolutely unbreakable, there are no log files *cough*
Joking aside, this kind of problem is hard to debug, but let's start with the basics:
Does it immediately crash or is there a delay or does it hang?
Is there an error message?
What OS do you have?
Is it 32bit or 64bit?
Which builds have you tried?
Have you tried running blackbox with explorer as shell?
Have you tried manually disabling all plugins (commenting their lines in plugins.rc)?
Do you have rights to write to the folder where blackbox is installed? (otherwise it might crash on not being able to open setting-files read-write..)
Have you eaten your cake yet?
:3