This is entirely my fault and I should be slapped for being so dumb, but I got impatient with a flash drive that hangs. I have a Rosehill USB 3.0 card installed on the W7 64 bit PC and have a USB hub run from the card.
I was transferring a video to a flash drive inserted into the hub and it was taking forever, the time remaining indicated 3 hours...well I was hoping to do the transfer quickly as I needed to get to work...as no progress was being made I clicked on cancel and it hung there for a while and finally I just pulled the stick from the hub.
That might have been a bad mistake because the screen immediately went black and rebooting brought me around to the same black screen. Nothing comes up, I mean nothing. The PC is running when I reboot but there is nothing on the screen.
Is there a way into the OS other than an old rescue disk I have?
Do you have 2 different video ports? Like a discrete AND a integrated graphics card(s)?
Try switching from the discrete to the integrated after resetting the BIOS to defaults on the mobo (there is a switch on the mobo that does that, or you can just pull the CMOS battery for a while). See if you can get into BIOS after doing that.