I think my computer is working again!!!!
I did some internet searching at work and found an article with a "quick fix" for my problem. It also had a bunch of comments from other users, some of whom found the fix successful, and some who didn't but offered their own methods to resolve it. Well, I tried the article's fix and it didn't quite work, so I tried one of the alternate solutions another user posted.
So far, so good!!
For the alternative fix, I went back to device manager after I'd rebooted in normal mode (surprisingly I didn't get the BSoD this time), found that they had reinstalled the defective NVidia Geforce FX 5200 driver. I clicked on it and chose "update driver." Then chose the manual install where they give you a list of drivers to choose from. There were 2: the regular Geforce FX 5200 and another that said "Geforce FX 5200 (Microsoft Corporation)". I chose the second one with "(Microsoft Corporation)", clicked install and when asked to restart the computer I did.
Voila! It booted up all the way as if nothing had happened. The resolution was reduced to 800x600 but I just had to go into Properties and Appearance to change it back to 1024x768.
I just couldn't believe that that was all there is to it. The guy who wrote this said it worked fine for him and he never got this error again. I thought I'd post this in case any of you fall prey to this and need a quick fix.
I can resume my usual computer activities (still going to continue to back things up of course)!!! *SQUEEEEEEEEEEE*
I am so, so, relieved!! :D