I did not experience this last night in my game and your repair did not sort this. So the two most logical things to look at are Addons and any new programs (in particular Multimedia players) you may have installed.

All the addons went out of date with Orsinium, so try the game with no addons selected. Although not sure why an addon would affect sound, it is an easy thing to test.

If you recently installed any programs, those may be suspect as to the cause of the issue if they do anything with sound files or added new codecs. If this was my machine, I would use System Restore to go back a few days, but that might make you have to redownload the update to the game.

Finally, when you say you checked the drivers, were they the drivers from the manfacturer's website or off a disk that came with your PC or parts? Your current sound drivers are 5 years old.

Ok here is the dxdiag from the other computer.

So looking in program files it seems I installed Ventrilo after ESO. Perhaps that is the issue? Not sure how to resolve that..