[HP G62 Notebook PC, Realtek ALC270, Mic, Internal] Background noise or low volume

the audio has a background sound like a crackling high pitched sound and I don't know how to fix it please I need help.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: alsa-base 1.0.24+dfsg-0ubuntu1
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic i686
NonfreeKernelModules: fglrx
AlsaVersion:
 Advanced Linux Sound Architecture Driver Version 1.0.24.
 Compiled on May 5 2011 for kernel 2.6.38-8-generic (SMP).
Architecture: i386
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: SB [HDA ATI SB], device 0: ALC270 Analog [ALC270 Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: henz 1656 F.... pulseaudio
Card0.Amixer.info:
 Card hw:0 'SB'/'HDA ATI SB at 0xd0400000 irq 16'
   Mixer name : 'Realtek ALC270'
   Components : 'HDA:10ec0270,103c1444,00100100'
   Controls : 16
   Simple ctrls : 10
Card1.Amixer.info:
 Card hw:1 'HDMI'/'HDA ATI HDMI at 0xd0310000 irq 19'
   Mixer name : 'ATI RS690/780 HDMI'
   Components : 'HDA:1002791a,00791a00,00100000'
   Controls : 4
   Simple ctrls : 1
Card1.Amixer.values:
 Simple mixer control 'IEC958',0
   Capabilities: pswitch pswitch-joined penum
   Playback channels: Mono
   Mono: Playback [on]
Date: Mon May 23 14:34:34 2011
InstallationMedia: Ubuntu 10.04.2 LTS "Lucid Lynx" - Release i386 (20110211.1)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_US:en
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: alsa-driver
Symptom: audio
Symptom_AlsaRecordingTest: ALSA recording test through plughw:SB failed
Symptom_Card: Internal Audio - HDA ATI SB
Symptom_Jack: Mic, Internal
Symptom_Type: High background noise, or volume is too low
Title: [HP G62 Notebook PC, Realtek ALC270, Mic, Internal] Background noise or low volume
UpgradeStatus: Upgraded to natty on 2011-05-18 (5 days ago)
dmi.bios.date: 11/07/2010
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: F.17
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: 1444
dmi.board.vendor: Hewlett-Packard
dmi.board.version: 69.26
dmi.chassis.type: 10
dmi.chassis.vendor: Hewlett-Packard
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnHewlett-Packard:bvrF.17:bd11/07/2010:svnHewlett-Packard:pnHPG62NotebookPC:pvr0595110000242710010020100:rvnHewlett-Packard:rn1444:rvr69.26:cvnHewlett-Packard:ct10:cvrN/A:
dmi.product.name: HP G62 Notebook PC
dmi.product.version: 0595110000242710010020100
dmi.sys.vendor: Hewlett-Packard