Everything else appears to be working but trying to left click anything opens inventory.
After I switched characters it started opening stats menu every time.

Can't access NPC's and move with left click unless I'm laggin I think and spam click.

Have you checked your mouse settings? If so, how about your windows settings for the mouse?

Windows mouse control panel settings doesn't detect a Microsoft mouse.
Logitech optical gaming mouse G400
Box has no information mentioning any special settings related to the button.

Plug and play setup...
I've tested other mouse buttons and everything else appears to function normally.
Just the odd opening/closing menu every time I clicked.

No more ideas? Just installed it so kinda annoying to uninstall it due to bein unplayable with no npc access...