computer kept asking for other user and now saying diskette drive 0 seek failure need help please.

tried to start in safe mode to do system restore doesn't work. then started saying diskette drive 0 seek failure not sure what all this means need help please.

(I have a custom built computer, there was just no other place to put this) I came home yesterday to find my computer turned off. After some looking, turns out the power supply had failed. I went out and got a higher wattage power supply, one that should suffice. It put it in, and my computer did turn on. Only issue is that now nothing will come up on my monitor. And I don't know why. I've taken out my GPU and run it off of the built-in graphics, with no avail. I just don't have any...