To me it seems like there is a problem with WireShare and Windows 10, the most recent updates. It worked fine for me (WireShare and others) until I the most recent W10 builds. I tried every suggestion and every possible solution that came to my head.
Keep in mind, WITHOUT ANY FIREWALL or ANTIVIRUS, it still does not connect or it partially connects like I said before - this only supports my theory that it has something to do with the most recent Windows Updates related to security.

well , yes there may be a chronic problem affecting the relationship between wireshare and windows 10 .

in the past , when there were problems connecting to limewire or lemonwire or any p2p app , the bottom left of the page would always show some activity ; the bars would change colour for a short time and then a note would appear saying something like , attempting to connect ;

but for the last 5 months those bars have been totally and completely unchanged ; just grey bars and the word connecting ; there has not been even one partial connection .

Do you port forward for those apps? This might be something to try. A google or portforward.com for your model would easily find instructions I'm sure. I found https://crowdsupport.telstra.com.au/...ing/td-p/84698 upon a quick search. But there's probably better descriptions out there. First you need to set up a static LAN address.

Why is it that universal plug and play does not seem to work so well as it did in the past .

No reason why UPnP should not work unless something in system, router or program settings has changed. However port forwarding done properly is ever reliable. Each program however needs to use a unique port. If two or more use the same port then it causes problems and fails.

MY MODEM APPEARS TO BE A TELSTRA MODEL TG797nV3 ;

WHAT TYPE OF ROUTER OR MODEM ARE YOU USING .??

Simply as a test you could try using an alternative computer account, perhaps temporarily setting one up and run WireShare to see if you have the same problems. You can of course delete a test account at any time.