No audio output device is installed

I have tried everything but I still can't get my sound back. Even when I click-control panel, systems, sounds, I don't get the sounds, games, video selection. Please help.

Thank you Takoi! It did not go quite as straightforward as you said for me, but got me onto the right road by using the menu you suggested after installing heaps of things I did not need and did not work and in fact caused other problems as you suggest. All I did was to buy new speakers (a leading brand, but 'not recognised' by Microbloodysoft, who led me a merry dance and I've now clogged up my computer with rubbish and adversely affected my screen display with their useless 'updates' out of desperation to get my new speakers to work) as mine were on the blink. I had to pretend I was re-enabling my port of choice (the same old one in the end, actually - after trying all the others, and getting nowhere until I found your advice) to re-enable my old speakers using Realtek. Anyway, I don't care if my computer thinks it's re-connecting with my old ones as my new ones are now working after 24hours of frustration - hoorah and thank goodness for that and your advice. You are very kind. I hope my sob story is of use to someone. Thank you again, Takoi.