I found solution by downloading a driver listed for my computer on Dell site. I actually tried to run this file twice yesterday and it didn't work. But today when I ran it, the installation worked and the sound works.
Thank you.

>If the sound card is integrated into motherboard, there are some things you could check:
>* Make sure it is activated at the BIOS setup
>* Sometimes you have to install the chipset drivers for the motherboard first before the drivers for the built-in stuff begins to work.
>
>>Thank you. I will check it again.
>>
>>>Im not an expert, but if you just reinstalled XP, the first thing that comes to mind is the drivers. I would check to make sure the proper drivers are installed for the audio card etc. You will have to find out what you have on the computer and google the drivers for that item.
>>>
>>>>I have no sound on an XP computer (recently reformatted and XP Professional installed).
>>>>
>>>>When I go to the Manager -> Devices I see 5 devices in the Sound, Video and Game Controllers. All devices show Working Properly.
>>>>
>>>>When I go to the Control Panel -> Sound and Audio Devices, the caption is "No Audio Device." The tab Audio and Default Device pull-down is grayed. That is, I cannot select audio device.
>>>>
>>>>What am I missing?