HELP ME TO GET BACK MY SOUND

Hello,
I cannot hear sound on my laptop since i reformat. if i want to play movie or mp3 it appeared ..."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." wHAT can i do? please help me.

system information:

OS Name Microsoft Windows XP Home Edition
Version 5.1.2600 Service Pack 3 Build 2600
OS Manufacturer Microsoft Corporation
System Name HOME-ECC659DAB9
System Manufacturer SAMSUNG ELECTRONICS CO., LTD.
System Model G10
System Type X86-based PC
Processor x86 Family 15 Model 76 Stepping 2 AuthenticAMD ~1803 Mhz
BIOS Version/Date Phoenix Technologies Ltd. D3NM.2496.20061011.LMK, 10/11/2006
SMBIOS Version 2.4
Windows Directory C:\WINDOWS
System Directory C:\WINDOWS\system32
Boot Device \Device\HarddiskVolume1
Locale Korea
Hardware Abstraction Layer Version = "5.1.2600.5512 (xpsp.080413-2111)"
User Name HOME-ECC659DAB9\samsung
Time Zone Pacific Standard Time
Total Physical Memory 512.00 MB
Available Physical Memory 128.20 MB
Total Virtual Memory 2.00 GB
Available Virtual Memory 1.96 GB
Page File Space 1.03 GB
Page File C:\pagefile.sys


PLZ HELP ME