urgent help

Okay, i really need help. I have no sound on my laptop.

And my cousin deleted some thing on my computer. Including the audio devices.

But i cant listen or do anything with sound. Like on one thing i try to listen to music

on media player it tells me this...

"Windows Media Player cannot play the file because there is a problem with your sound device. There may not be a sound device installed on your computer, it may be in use by another program, or it may not be functioning properly."


Any idea, what i can do?? But i dont want to have to buy anything.
Or is it a MUST.

 

Moving this to hardware...

 

What is the make and model of your computer? Sounds like you need device drivers....