BIOS update- black screen, hard disk access how to fix

DELL support center has been bugging me to install updates for a while after concluding that some drivers were out of date. Intel chipset and a couple of other things. I usually put off all sort of updates except for strictly security based ones for the OS (which in this case is Windows 8.1... yes, I didn't update to Windows 10 either). 

Eventually today I caved in, and said update to all in the Support Center, which included the BIOS.

The BIOS update was a bit different and it wasn't clear that its update had concluded. It had its own dialog box, separate from the DELL Support Center window, which was quite confusing. I first clicked on "finish update" on the DELL support center window. This told me that this would trigger a restart to finish installing the different components that had been updated. Not wanting to have to restart the computer twice I wanted to make sure that the BIOS update had also finished its thing and clicked finish on that. This proceeded to start updating the BIOS. 

I was a bit surprised at this, but didn't want to interfere, Interfering with a BIOS update isn't well advised. About half a minute went by with no problems. Then Windows decided to restart the computer without giving me any possibility of stopping it. 

I hoped that this restart was an automated part of the BIOS update. It hadn't finished, it was only at about 85%, but I thought "perhaps it needed to do this in order to finish the update entirely". Surely the software would not allow a restart to happen if it could jeopardise the machine. The machine started making noise and was clearly accessing the hard disk, so I let it do its thing.

Several hours later I can see that  things have clearly not gone well. The screen is black, and I believe that the noise I'm hearing is "looping". I unplugged all peripherals, apart from screen, keyboard, and mouse. Eventually I turned off the machine. I gave it half a minute before plugging back in. No change. It lights up, makes noise. Nothing on the screen.

I've plugged the monitor out of the GPU and into the HDMI outlet for the base computer. The screen is still saying that it is not getting any feed and going to sleep automatically.

This is so frustrating. I need this computer for work, I can't afford a new one, and not a great deal of time to be mucking around with the inside of a machine. Most of all it's annoying that it looks like trying to do the right thing has completely [something you do with a screwdriver]ed me over.

Are there any measures outside of dropkicking the machine out the window, or replacing the motherboard, that could potentially remedy this situation?

Edit: there's a solid orange light coming from the motherboard.