OK, was abel to get back into Windows 10, go to Control Panel, and restore Windows 8.1. However, now I have another issue. I can't tell if this is related to the "System Thread Exception Not Handled Error" or not. But the problem was happening simultaneously, when I started getting the BSOD and the error message. (Incidentally, this boot/loading issue with the monitor going into Power Save never happened before I started seeing this error message, which is why I think the 2 are connected.)
The system is not loading and the monitor immediately goes into Power Save mode. It was happening before as well but when I put the Windows 8.1 boot disk, somehow the sytsem did start once. Now it's not starting with even that. Antoher thing, when it tries to load for the very first time (without boot disk in DVD drive), the computer makes very audible and grunting noise! WTF. I've never had this happen before. Is this a starter problem? The monitor just doesn't seem to recognize it.
Could the "System Thread Exception Not Handled", which suggests that the driver are incompatible, may have resulted in hardware failure? When I got into my system, I went to Dell, downloaded and ran all drivers to make sure I had the latest and greatest for Windows 8.1. Prior to all this, I seemed to be having minor malware issues as well with some of my commonly-visited sites not loading quickly enough and one time I was being redirected to phishing sites. I purchased Hitman Pro to resolve this and ran it, got rid of certain malwares, I thought. I did all this when I was able to log in and restore Windows 8.1., i.e., all under 8.1.
Am trying to ferret out if this is a (1) hardware issue involving my power source or starter or (2) malware/driver-induced hardware issue which started from "System Thread Exception Not Handled." If starter/power source, I have a similar Dell model which died 3 years ago (XPS 8300) from which I think I can poach similar parts. Sorry, this is getting more complicated now and has played out in an unexpected manner.
Latest Update: Now I can't even turn off the computer. Left the comptuer on for a while with the montior not recognizing. Can't turn the system off without turning off power. The starter button doesn't respond. And when I restart, the system attempts to load but the power button's light is off. It looks like the whole system has disintegrated.
Thanks so much for comments guys. I tried the MS Media Creation Tool, copied that to a CD and tried to boot from there. Nothing. Then called that Microsoft line -- apparently that number is dedicated to Dell computer users; they don't recommend upgrading to Windows 10 (Well, then, why was I enticed into upgrading for crying out loud?)
Edited by techgnosis, 24 December 2015 - 01:32 PM.