Installed from a USB stick- on restart, HDMI not recognized

[phildo]

I created a boot USB from debian-9.0.0-amd64-netinst.iso (via unetbootin), and booted into it on a PC.

It said "there are sometimes problems with using unetbootin, proceed at own risk", or something like that, but I just went along anyways.

It then said "there are some non-free drivers your system needs- put in media to install them now?", and I advanced _without_ doing so.

Then it said something like "do you want to install as EIFI" (or something), and said it would wipe the current OS's (in my case, Windows 7, I think), and I said ok.

So then, it finished installing, and rebooted.

But upon reboot, my monitor just says "HDMI NO SIGNAL" (as though it's plugged in to nothing). I've rebooted again and again, unplugged/replugged/etc..., and I just have 0 acknowledgment of anything from the monitor's perspective.

So, I've created _another_ boot USB (again from debian-9.0.0-amd64-netinst.iso), but this time just via the 'dd' utility (first converted the .iso to a .img). The problem is, I can't get to the bios, or anything.

So, is there some standard key to hold down to try installing from a USB? Is there something I can do to get enough visibility to start over? Or is the PC just bricked?

Edit: Just to be clear, the monitor works fine. Tried plugging it in to another computer and everything's great. Also, tried VGA, and have the same problem (no VGA signal of any kind).

[Dai_trying]

It could be a graphics issue, I have read other users having problems similar to this without graphics drivers (a search of this forum will list quite a few) but in order to proceed I would try a live-cd first to see if it will get you to a desktop session and then you would have a base on which to either repair your system or at the very least you would be able to gain access to command line to get some information that anybody wishing to help you would need.
If you get a live session running you could install inxi and then post the output of inxi -F (hardware specs)

[phildo]

The problem is, I can't even see the bios.
I still have the USB stick- if I press the power button with the stick in, and try pressing delete on the keyboard (the button I had to press to get into the boot menu the first time), nothing happens. (To be clear, by "nothing happens", I mean the monitor's screen doesn't flicker, doesn't notice any change whatsoever from the HDMI or VGA being totally unplugged).

Why do you think a live-cd would work differently than a USB? (I don't have a cd burner...) Like I said- I can't even see the bios.

Any further help would be greatly appreciated!

[Dai_trying]

Live-cd is just a terminology for the iso image that has a live system on it which will boot into a "live session" it can be used from a usb stick the same as the install image. Although if you cannot even get the install image to boot I am now uncertain as to whether it would work, but it is what I would try...

[peer]

no need to convert the iso to img

the following command will copy your iso to an usb (on /dev/sdb) form within the directory where the iso is stored.

sudo dd if=debian-9.0.0-amd64-netinst.iso of=/dev/sdb bs=4M

but I would try a live os first.

[phenest]

The problem is, I can't get to the bios, or anything.

When you turn on your your PC, there is no manufacturer splash screen? The monitor stays off, yes?

Or is the PC just bricked?

If it is, it's nothing to do with Debian. Does the PC power up?

[phildo]

Ok. I found the problem.

Yes- the monitor does not show the PC manufacturer's splash screen, or anything.
The reason I assumed it was Debian is that it was working fine on windows, I went through the installation for USB (still working fine), and then it said "ok I'll restart and you'll be in Debian", and from that point on, nothing showed up. It would have been a huuuge coincidence if the motherboard pooped out _right_ then...

But the problem was this: the monitor was plugged into the motherboard, _not_ the graphics card. For some reason, windows was ok with this. Debian was not. All fixed!

[phenest]

There's a lesson to be learnt here. I think you know what it is.