Are you sure that you have the weapon equipped? If you are in the 1st person mode then your weapons will show prominently 3d person you will see you character with weapon in hand. Right mouse controls the right hand and left mouse controls the left hand.
You character should swing their weapon when you click on the mouse key. If not then maybe you should check your key mapping.
Yes. I am holding my sword and am wearing all the armour I've acquired to date, oldman.
[ I've looked at myself in 3rd person mode

]
However, on meeting an enemy who I hope to fight, mouse clicking of either button just brings up a sort of star shape on screen with the options of Skills, Magic, Items or Map !!
And I have no idea how to map keys

Can you help at all, please ??
I never had this problem with Morrowind OR Oblivian.
[ Hi looney4labs

]