Don't delete anything until it is proven to be the faulted cause of the problem. (or, don't get a lobotomy just because you have a headache).
You have no warnings in device manager, good. Go here:
Control Panel>Sounds and Audio Devices>Audio>Sound Playback>Default Device
Is your sounds card showing correctly?
no, change to show sound card.
no, it says "no mixer device," come back and report that if that's the case. Stop here.
Yes, click "Volume" tab>Speaker Settings>Advanced>Speakers>Speaker Setup
Is your speaker setup selected correctly?
no, make it right.
Yes, check which socket you are plugging in your speaker to, it is normally green for R+L stereo or R+L front.
Sound work now?
yes, Cool.
no, While at the "Volume" tab, tick the box labeled "Place volume icon in the taskbar" (to put checkmark in box) then click "Advanced" button right there. Make sure no Mute checkboxes are checked. Make sure Master Volume is not lowered to the bottom, same for "Wave" or you will get no sound.
Works now?
yes, cool.
no, take 2 aspirin and call me in the morning.