Thanks, Fellippe and xra7en!
This is probably more of a Windows OS operator error issue than a QB64 issue. Feel free to point me somewhere else.
I downloaded, unzipped and ran QB64_1.4 on another Windows 10 desktop (asus) and everything worked just fine. On the Windows 10 desktop (hp) I am trying to get it to work on, I think I mangled something by multiple downloading and deleting of the QB64 system. (I didn’t find an uninstall entry in the Control Panel.)
The best I can remember, I did the following:
•   Downloaded the QB64_1.3~.7z zip file and unzipped it under the “Program Files” folder. (This was my first use of .7z.) I saw where that location is a no-no, so I deleted that subdirectory.
•   Repeated the process for the 1.3 version to the “Downloads” subdirectory, again using the .7z file.
•   Tried to create the “Hello World” program and ran into the “flash” output screen problem.
Per Fellippe’s suggestion, I referenced the Terry Ritchie tutorial. I deleted the QB64_1.3 subdirectory. I downloaded the QB64_1.4 file (.zip this time) to the desktop and unzipped it to a desktop folder. Created a program of just PRINT “HW” and ran it from the IDE. It just flashed like before.
Per xra7en’s suggestion, put in statement “INPUT i” with same result. Put in FOR NEXT loop and gradually increased the count to a billion. Same result. This is all running from the IDE. Running the exe from Windows File Explorer results in the error: “Windows cannot access the specified device path or file. You may not have the appropriate permissions to access the item.”
Running the .exe using cmd results in “Access is denied.”
•   I know next to nothing about environment variables but I did look in System Information and there are no environment variable entries containing the string "QB64".
Thanks for any inputs!