Click Start, right click on My Computer and choose Properties. Click Hardware on the top and then choose Device Manager. Verify if you have anything with a yellow question mark in there and write in here what is showing up.

Also what brand of computer do you have?

Hi thx for ur reply.

Brand: HPc, intel inside, centrino.... don't really know.

Yes, I have 3 yellow question marks.
? Other devices (main category)
?! Multimedia Audio Controller (?mark with a !)
?!PCI Modem (also a ?mark with a !)

When I click at Multimedia AC I can choose between General, Driver, Details and Resources.

General:
Multimedia Audio Controller

Device type: Other devices
Manufacturer: Unknown
Location: PCI bus 0, device 31, function 5

Device status:
The drivers for this device are not installed (code 28)
To reinstall the drivers for this device, click Reinstall Driver.
Button: Reinstall Driver

Device usage: (scroll)
Use this device (enable)
or
Do not use this device (diable)

Have tryed the "reinstall driver button":
What do you want the wizard to do? (to options)
x Install the software automatically (Recommended)
x Install from a list or specific location (Advanced)

Have tryed both options but I don't manage to finish them. Any advice?

Thx :-|

From what I have read it sounds like you have found about three devices that do not have drivers installed. If the computer is like many XP systems they have omited providing you with CDRoms with the hardware drivers and operating system. If you can get online, I would suggest you visit the HP Website ( http://www.hp.com ) I think, and with your model number in hand you should be able to download copies of several of your drivers. Keep in mind the device that may be unlisted ( unknown ) may well be a software modem so you may find if you get the entire modem driver package it may also install that unknown device. I would say the multimedia audio controller driver should restore your sound. Make sure you have uninstalled whatever driver you tried to install if it is not working prior to attempting to install new drivers.

How do I know what to download? And I think my model is G-1517 but I'm not sure.

Do I need to download an audio driver or an audio device?

Thx

Generally there is a model number located somewhere on the outside of the system if it is made by one of the big makers like HP, Compaq, Dell, Gateway, ETC. Go to their Website which I think you said you have an HP, and then you should find a link to support on that page. In the case of HP the USA/English version of this page is:
http://welcome.hp.com/country/us/en/support.html
Once there you would enter the model number as shown in the examples on the page. It should then direct you to the drivers for your particular model. Clicking on the hyper link for each driver should allow you to download the driver files. For most who are not advanced users you would likely find it best to save them to your desktop. After they have downloaded, clicking on the desktop item should run the driver install program in most cases. If the download is a ZIP file you may find it nessesary to extract the files to a temporary folder and then locate the INF file and right click and select the install option, or using Add New Hardware option in the control panel find new hardware and then point to the temporary folder for the hardware drivers to be installed.

I would recommend you download all drivers related to your system if possible and then save them off to a CDRom or other storage for future use if possible. It is always handy to have a copy of the drivers around once you get the computer going correctly just incase something happens to take them out. After you get your system working correctly you may wish to consider a program like Driver Collector to allow you to save even the drivers not found elsewhere for download. You should be able to get the Driver Collector program at:
http://www.majorgeeks.com/download.php?det=3982
It will locate and save the drivers to a folder where you can then copy them all to a CDRom and then have them on hand if you need to reinstall them for some reason.

Hi. Thx for ur advice, but I have still not solved my problem with the sound. I got HPc mod MS 2137. I have visited www.hp.com, tryed do download audio driver. Have tryed realtec AC97, SP28282 and SP26490, but still I don't have an audio devicer. What have I done wrong?

As mentioned by Gemini14 above you should not have any Question Marks or Exclaimation Marks in your Device Manager. If you do it means that the driver is either not installed, incorrectly installed, or is simply the wrong driver. Whatever the case is make sure you uninstall any driver that may be shown if there is an exclaimation or question mark before you proceed to attempt to install another driver. In some cases it may even be nessesary to disable AV software or possibly spyware tools that control new entries to the registry. I will also mention I have found myself without sound after Windows Update sent me the wrong driver and I needed to uninstall the driver they sent to me and install the one that come with my motherboard CD. Use the Device Manager ( which you can get to from the Control Panel > System > Device Manager button ) to confirm you are getting the new version of the driver installed. If it shows it has not been installed it is possible you do not have the correct driver for the system or you have installed the wrong driver which may need to be uninstalled ( disabled ) prior to reinstalling the correct one. This may sound strange or silly, but is there any possibility you have the system muted or the sound otherwise turned off? I think you said the system is a laptop so I am not even going to mention about the speakers being plugged in and turned on if they are powered. Ideally when you are done and no longer have any problems shown in the Device Manager you should have sound if the speakers work.