Windows 8.1 & Skype

I've been helping a friend with her Windows 8.1 PC and various issues she has had with it.

The one area that seems to be a persistent issue is using Skype.

The issues is that when she receives a call there are sometimes one, sometimes two Answer / Answer with Video / Decline sets of buttons. When clinking Answer the ringing tone continues although she can then be talking to the caller. Even when the visible Skype has been closed the ringing continues - though there's then a Skype icon in the System Tray which can't be closed, or anything else done with it. The only way to stop the ringing is to go to Administration / Services and Stop the Skype process - not ideal.

There are other Skype issues seemingly related to two Skypes running. She's often said to me that it always looks as if there are two Skypes running.

Although the Skype integration with her Hotmail has been removed, and her Skype account disconnected both from her Hotmail & Facebook accounts, the problem persists.

The PC is set up so that that old style desktop is in use virtually all of the time. Skype 6.21 is installed on that desktop. There is no Skype visible on the Widows 8.1 Start screen nor in the Apps list there. At one time Skype 'modern was installed but that was uninstalled. The only Skype in Control Panel/Programs is Skype 6.21. I seem to recall reading that Win 8 'Modern' Apps don't appear in that list. In which case where is V.3.1 coming from?

I ran Belarc Advisor on it and it shows 3 Skype entries in the Software Versions & Usage section:
Skype - Skype Version 3.1.1005
Skype Technologies - Skype Updater Service Version 6.8
Skype Technologies - Skype Version 6.21

So Belarc is reporting 2 Skypes (I've ignored the Updater as that is presumably associated with 6.21). I've no idea where V.3.1 is, what its effect is or might be, I can see no reason - apart from historical - for it to be showing.

Is Belarc mis-reporting V.3.1?
Is there a remnant of V.3.1 that's causing the problem?

I've installed Revo Uninstaller but it only shows V.6.21.

How can I completely dispose of V.3.1?
Whether or not this is the problem I don't know, but clearly I have to deal with the problems that I can see and eliminate everything possible.

Any thoughts on how to progress?

I realise I probably haven't written a very clear post but hopefully there's enough sense in to give the picture and, hopefully, help someone to point me in the right direction to resolve the issue.

I may well be barking up the wrong tree.

I believe for windows 8 there is an app, which comes installed as standard.

You can also download and install the Application that is used on previous versions of windows (which I have done, so all machines work in the same way.

If you were logged in to both you might well get two calls coming at once, not sure why it would carry on ringing though.

I have remoived the app, as that is the version which I thought was less capable and do not have this problem. Actually, I must check it has not re-installed itself as several others of the junk items seemed to have done after one of the updates.

There is no sign of the pre-installed App, indeed I uninstalled it early on, but there still appears to be a remnant of it around.

how to get rid of the remnant is the issue.