I think I can call this one solved.
axe0, after much experimentation on my own & several new BSOD's I think I hit upon my problem. In almost every later BSOD instance, I had Firefox running. I also had dozen's of add-on's & dozens more of them installed, uninstalled, enabled & disabled etc... Some conflicted with others at times as well. I had come across a Firefox forum entry about something like this causing someone else getting many BSOD's for this same reason. They ended up resetting Firefox to a clean no add-on original state(done in Firefox settings) & their BSOD's stopped. I have done the same thing & have even gone as far as not using Firefox at all (temporarily) & switched to Chrome for a while until this proves successful. I have not had a BSOD since. I have now been BSOD free for 20 days. Previously, I never went more than 3 or 4 days without a BSOD. So it looks to me as if Firefox was the final problem/cause in addition to the previous driver & Dell software issues. Thank you for your assistance. I will call this solved now. If anything new arises, I will start a new thread. Again, thank you.