Ok, but there is one thing with your initial post that I put as questionable.
You say you had a software that overrun your RAM. First question - what kind of feedback made you come to that conclusion?
Then the shutdown thing. If it is true that the ram was filled up by one app/game, then this will be an expected reaction of the computer, because now it start use the page file that is way slower than RAM - maybe even growing out of control if the file size is set to auto (I don't know if Windows has a working protection mechanism for this).
So - let me droddle a little about this - And then you used the kill switch. Problem here is that if the page file was in progress of expanding out of control, then you can have interrupted two tings that play along here:
- The content of the page file(s) or what is left.
- File system metadata, of file table (don't remember the correct term for NTFS just now). A constantly growing file will also cause almost constant change of the file table, and interrupting that may cause corrupted file system.
But the greatest issue is your bios cannot find your hdd's. Afaik there should be no connection between software/file-system issues and the electrical connection between bios and hdd. So let's focus on that first, to get your system to boot.
I'd want you to shut down the computer completely. That also include remove the power cord. Then - when no power connected, you hit the power-button. I know, I know this sounds like an irrational plan. But the idea is to flus hout any residual voltage from the power supply, to ensure any residual settings that can cause functional failing get blanked before next attemt.
Try that and see what happens.
[edit]
Just have to ask : Did you do anything else in the meantime, other than trying to reboot the computer?