driver Vaio pcv-a31l vg-ra840g

You can try windows update first to locate the audio driver.

If no go, download the realtek drvier from the link below.

http://www.afterdawn.com/software/drivers/sound_card_drivers/realtek_high_definition_audio_codec_windows_7_vista.cfm

Restart computer to take effect.

If still no go, there are many choices. Do you want to install Internal PCI or External USB audio devices?

if you have  unknown devices in device manager, you can use this procedure to identify them :

1-visit the motherboard manufacturers support site, for downloading drivers
2- use windows update >optional updates to find them

3-Start>Programs>Accessories>System Tools>System Information.
Now select  "Components" and highlight "Problem Devices".
All hardware devices with a driver problem will be listed here.
Make a note of the first line of the PNP Device ID line of the entry. It will show a Vendor number and a Device number (VENxxxxDEVxxxx) both four digits long.
Look up those numbers here:   http://www.pcidatabase.com/index.php

This will tell you the manufacturer and the chip number.  
Check the manufacturer's website first or google them - or post them here

If your LAN is running, you can also use windows update> optional drivers, or  use slimdrivers : https://www.slimwareutilities.com/slimdrivers.php

Nobus
first PNP Isee is:
PNP Device ID      HDAUDIO\FUNC_01&VEN_10EC&DEV_0880&SUBSYS_104D0500&REV_1008\4&986038D&0&0001

but I get no vender search results
any suggestions

I did Windows updates at the very start, non found to resolve audio issue

Have you tried the Realtek driver?

http://www.afterdawn.com/software/drivers/sound_card_drivers/realtek_high_definition_audio_codec_windows_7_vista.cfm

that shows as Realtek 880 High Definition Audio; vender is realtek
you best download it from the Sony site :  http://esupport.sony.com/US/p/select-system.pl?PRODTYPE=1

put in your model - or let it be detected; there's also "how to find the model #"

this i say because :  pcv-a31l vg-ra840g  is no valid number

sorry PCV-A31L VGC-RA840G

nobus
I went to Sony's site  http://esupport.sony.com/US/p/select-system.pl?PRODTYPE=1
this is where I only found Windows XP driver for PCV-A31L VGC-RA840G

Sorry, my screw up
it's an issue with "Multimedia Video Controller"
When I try to use "windows Media Player" I get error
"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"

there are vista drivers on that site - but i fear these won't help  - UNLESS you use them in a 32-bit OS

here the realtek 64 bit codec :  http://www.realtek.com/downloads/downloadsView.aspx?Langid=1&PNid=24&PFid=24&Level=4&Conn=3&DownTypeID=3&GetDown=false

Nobus
I installed the Vista 64 bit driver and the sound works now
but I still have an exclamation on "Multimedia Video Controller" in device manager
I may just leave it and use the PC this way.
Thanks

thanks

i suppose it worked?