The battery is an interesting idea because my battery has been through more then most. After Sandy I had no power for two weeks and I had the power supply unplugged for five days during this incident so maybe there is something to that.
Fwiw, I had to upgrade to a more-powerful power supply around 3-4 yrs ago (purchased from Drachillix 
) and had no isssue with licensing, etc. Put in new video card and more RAM at same time. IIRC, I was still with Win7 if it matters.
Just a ‘data point’, I guess.
I replace power supplies all the time and have never seen any problem with licensing. That information should be in the BIOS/motherboard. This seems like a case of post hoc ergo propter hoc.
Yes, if your CMOS battery is not keeping the proper date and time, it will go into “non Genuine” mode. So it sounds like that is a possibility.
If the date is wrong by too much, the computer is unable to use any encripted connection where the certificate/key is too “old” or too “new” – that is, where the certificate date is not valid for the date the computer thinks it is.
Also, if the date is wrong, it can trigger a revalidation request, because the computer date is before the validation date.
“invalid” + “no validation response” = “non genuine”.
It sucks that Dell wouldn’t suggest that you might be able to fix the problem by resetting the date.