Thank you, Hansb. I appreciate that.
I'd like to add the following: As an experiment, since I have 16GB of RAM, I completely turned off the Windows Paging File so that Windows would just use the RAM without any hard drive Page File.
There was no Out of Memory error message when leaving the computer on overnight.
I then turned the Windows Paging File back on (I tested it with both "Let Windows Manage the Page File" and with me setting specific values). And sadly, the "Out of Memory" warning sadly appeared again...and again there were no programs whatsoever running.