AUDIO DEVICE PROBLEM

I have a gateway laptop mx6455 and then sound beeps through the speakers but when i try play video or music it says "Windows Media Player cannot play the file because there is a problem with your sound device. There might not be a sound device installed on your computer, it might be in use by another program, or it might not be functioning properly." i tried to download ac97 driver from the paretlogic thier scan said there was a problem and gave them 35.00 and still no luck

i tried to remove and reinstall realtek ac97 and the wizard went through it process and then flashed device cannot start code 10

Hello,

Please try to install the driver from Gateway instead:

http://support.gateway.com/support/drivers/dlcenter.asp

that was no luck i treid clicking on the sync to look for another device it says no device found but in device manager it has a yellow question mark
the speakers beep on start up but that is it .....is the sound card replaceable in a laptop?