My Speakers arnt working

Hello,
So I was listing to my music like i always do. I never go without it. My two year old son came in and shut my enire computer off by its power strip. Everything still works but my speakers. No sound at all Ive tryed everything. its not muted its all sopose to be working the light on my speakers is on saying they are still working. when i go into Windows Media Player is says Windows Media Player cannot play this file. The Player may not support the file type of codec that was used to compress this file. Umm... I dont know what that means. But please help me im going crazy stuck with a radio. best way to get back to me is my e-mail.

jessica_bentley91@yahoo.com

Please make the title say how to fix your speakers or somthing cause I dont check it often but I will to fix this problem. Please help.