Windows 8 safe mode is kind of hard to get into.
One option is to quickly press shift f8 after your POST splash screen and before the windows splash screen. You have to be quick.
The other option is to wait until the display says windows 8 has failed to start, what do you want to do? There should be an option to go into advanced, and a screen with blue background goes up. Go into advanced, again, and a bunch of options that includes safe mode and safe mode with network, etc.
But in your situation it sounds like it won't ever get into that situation, because even if you put in your windows 8 cd it gets to black screen. So I say good luck with shift f8
Have you tried to disconnect the HDD yet? It really sounds like your HD is to blame.