Soung from skype works, no other sounds work

Hello,
Sounds from my speakers work fine when I am using Skype......but when I go to play any other media, like lets say a youtube video.....I can't hear a thing.

I don't know why. I go to Control Panel --> Sounds and Audio Devices.....it says I have no audio devices. This doesn't make sense if I can make calls from Skype just perfectly.

I get an error every time I start my computer about an I/O problem....could this be it?

-Thanks