Thank you all for your replies...
(In line with (what I call) "corny" late night show from a North American TV network (one with 3 letters in network name) - and a "cool" (?) character with black fuzzy hair who introduces the show host - the "cool" gentleman when he assesses the answers from the guests says - …)
ALL THE ANSWERS ARE CORRECT
Firstly, I have done well over a hundred recompilations, since - and ALL "behave" correctly now - the only change is that I used SYSTEM. I did not view Task Manager (unfortunately) or run as "Administrator" at the time.
Secondly, when the problem started occurring - I had just used _HIDESCREEN (for the first time ever) - the reason why I was trying HIDESCREEN was that I was getting an annoying screen flickering of the consol/output graphic screen (these flickering about say 10 times a second over say 10 seconds plus and the FULLSCREEN was displaced (i.e. not fullscreen anymore). For another future post, I am trying to reproduce the same effect in MINIMAL CODE - I do not want to submit my 500 line program - this minimal code is in itself proving to be quite difficult for me as a bare bones 10 or so line program "behaves itself" - and step by step line removal from my 500 line program (expectedly) causes all sorts of errors - hopefully soon I will have a short program to reproduce the flickering effect.
Coincidently, when the "X" series of programs was being first implemented, my computer had just "recovered" from a virus attack (more correctly, I think you would call it a 'ransomware' attack) - just about everything (that was physically connected such as usb sticks and SDHC card) and the C:\ D:\ (recovery drive) and E:\ (Tools) were severely affected. Windows 10 security was alerting me to the fact that something bad was happening - but obviously could not stop it (something new). I was not prepared (never encountered a virus attack before - I probably did not press the right keys at the right time in the right sequence at the right place.... All this made me both very sad and very angry - consequently I am using Windows 10 Folder protection for all drives A,B,C,....,X,Y,Z and so everytime I run an application (for the first time) I decide whether or not to allow folder access permission, etc. Without further details (in this post), except to say, the virus occurred because of something of interest to me, was mentioned on YouTube - I did not view the YouTube (I never use YouTube on my laptop) - somehow YouTube app (or something) downloaded, as well as a whole host of other things (like diskcleaner or so), all so very quickly, and when I first noticed something I suspected was going wrong - there was a brief (say quarter of a second) window written in Russian (I think) but I could not do a screenshot in time.... anyway hence why I am "Folder protecting" everything.
The virus attack compromised say about 1 Terabyte - luckily I did not have my 8 Terabyte drives attached - but as a result, instead of working with 10 GB for the [abandoned, outdated and now likely malicious qb64 dot net website - don’t go there] uploads - I had to extract from 8 TB - I only just recently been able to reduce 8 TB to 220 GB (of potential relevance for [abandoned, outdated and now likely malicious qb64 dot net website - don’t go there] uploads) and it took windows 10 about 4 days (24/7) just to block copy 1.5 million items (220 GB) - for precaution, all usb sticks which directly or indirectly were attached, are quarantined.
Many thanks again
p.s. I have a feeling that there is a bug in Windows 10 folder protection - it allowed a new program (I called A.bas ) to actually run and output before Windows 10 required me to grant permission.