CPU usage 100% on my Inspiron E1505

I have an Inspiron E1505 laptop. Over the past couple of months, the CPU usage becomes 100% 15-20 minutes after booting the machine for no apparent reason.

When I check the CPU usage on Task Manager and then close the processes hogging the CPU, the CPU usage does not reduce and instead some other process start hogging it.

I read that Hijackthis provides an early troubleshooting aid. Ran it on my machine. Pasting the results here.

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Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 10:28:01 AM, on 4/21/2007
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16608)
Boot mode: Normal

Running processes:
C:\WINDOWS\System32\smss.exe
C:\WINDOWS\system32\winlogon.exe
C:\WINDOWS\system32\services.exe
C:\WINDOWS\system32\lsass.exe
C:\WINDOWS\system32\Ati2evxx.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\Program Files\Intel\Wireless\Bin\EvtEng.exe
C:\Program Files\Intel\Wireless\Bin\S24EvMon.exe
C:\Program Files\Intel\Wireless\Bin\WLKeeper.exe
C:\WINDOWS\system32\spoolsv.exe
C:\Program Files\Common Files\Apple\Mobile Device Support\bin\AppleMobileDeviceService.exe
C:\Program Files\Common Files\Creative Labs Shared\Service\CreativeLicensing.exe
C:\WINDOWS\eHome\ehRecvr.exe
C:\WINDOWS\eHome\ehSched.exe
C:\Program Files\McAfee\MBK\MBackMonitor.exe
C:\PROGRA~1\McAfee\MSC\mcmscsvc.exe
c:\program files\common files\mcafee\mna\mcnasvc.exe
c:\PROGRA~1\COMMON~1\mcafee\mcproxy\mcproxy.exe
C:\PROGRA~1\McAfee\VIRUSS~1\mcshield.exe
C:\Program Files\Common Files\Microsoft Shared\VS7DEBUG\MDM.EXE
C:\Program Files\McAfee\MPF\MPFSrv.exe
C:\Program Files\Dell\QuickSet\NICCONFIGSVC.exe
C:\Program Files\Intel\Wireless\Bin\RegSrvc.exe
C:\Program Files\SiteAdvisor\6253\SAService.exe
C:\WINDOWS\system32\svchost.exe
C:\Program Files\Canon\CAL\CALMAIN.exe
C:\WINDOWS\system32\dllhost.exe
C:\WINDOWS\system32\Ati2evxx.exe
C:\WINDOWS\Explorer.EXE
C:\PROGRA~1\McAfee.com\Agent\mcagent.exe
C:\Program Files\SiteAdvisor\6253\SiteAdv.exe
C:\Program Files\McAfee\MBK\McAfeeDataBackup.exe
C:\Program Files\Conexant\AccessRunner ADSL USB\CnxDslTb.exe
C:\Program Files\iTunes\iTunesHelper.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Program Files\Common Files\Teleca Shared\CapabilityManager.exe
C:\Program Files\iPod\bin\iPodService.exe
C:\PROGRA~1\McAfee\VIRUSS~1\mcsysmon.exe
H:\HDD\SW\HiJackThis.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = www.google.com/ig/dell?hl=en&client=dell-usuk&channel=us
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = about:blank
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://go.microsoft.com/fwlink/?LinkId=69157
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://go.microsoft.com/fwlink/?LinkId=54896
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Bar = http://us.rd.yahoo.com/customize/ie/defaults/sb/msgr8/*http://www.yahoo.com/ext/search/search.html
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = http://go.microsoft.com/fwlink/?LinkId=54896
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = http://go.microsoft.com/fwlink/?LinkId=69157
R1 - HKLM\Software\Microsoft\Internet Explorer\Search,Default_Page_URL = www.google.com/ig/dell?hl=en&client=dell-usuk&channel=us
R3 - URLSearchHook: Yahoo! Toolbar - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - (no file)
O2 - BHO: Adobe PDF Reader Link Helper - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Program Files\Common Files\Adobe\Acrobat\ActiveX\AcroIEHelper.dll
O2 - BHO: (no name) - {089FD14D-132B-48FC-8861-0048AE113215} - C:\Program Files\SiteAdvisor\6253\SiteAdv.dll
O2 - BHO: DriveLetterAccess - {5CA3D70E-1895-11CF-8E15-001234567890} - C:\WINDOWS\system32\dla\tfswshx.dll
O2 - BHO: scriptproxy - {7DB2D5A0-7241-4E79-B68D-6309F01C5231} - C:\Program Files\McAfee\VirusScan\scriptsn.dll
O2 - BHO: (no name) - {7E853D72-626A-48EC-A868-BA8D5E23E045} - (no file)
O2 - BHO: QUICKfind BHO Object - {C08DF07A-3E49-4E25-9AB0-D3882835F153} - C:\PROGRA~1\TEXTware\QUICKF~1\PlugIns\IEHelp.dll
O3 - Toolbar: McAfee SiteAdvisor - {0BF43445-2F28-4351-9252-17FE6E806AA0} - C:\Program Files\SiteAdvisor\6253\SiteAdv.dll
O4 - HKLM\..\Run: [MSKDetectorExe] C:\Program Files\McAfee\SpamKiller\MSKDetct.exe /uninstall
O4 - HKLM\..\Run: [SiteAdvisor] C:\Program Files\SiteAdvisor\6253\SiteAdv.exe
O4 - HKLM\..\Run: [McAfee Backup] C:\Program Files\McAfee\MBK\McAfeeDataBackup.exe
O4 - HKLM\..\Run: [MBkLogOnHook] C:\Program Files\McAfee\MBK\LogOnHook.exe
O4 - HKLM\..\Run: [Adobe Reader Speed Launcher] "C:\Program Files\Adobe\Reader 8.0\Reader\Reader_sl.exe"
O4 - HKLM\..\Run: [Sony Ericsson PC Suite] "C:\Program Files\Sony Ericsson\Mobile2\Application Launcher\Application Launcher.exe" /startoptions
O4 - HKLM\..\Run: [mcagent_exe] C:\Program Files\McAfee.com\Agent\mcagent.exe /runkey
O4 - HKLM\..\Run: [CnxDslTaskBar] "C:\Program Files\Conexant\AccessRunner ADSL USB\CnxDslTb.exe" "Conexant\AccessRunner ADSL USB"
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\QTTask.exe" -atboottime
O4 - HKLM\..\Run: [iTunesHelper] "C:\Program Files\iTunes\iTunesHelper.exe"
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O4 - HKCU\..\Run: [BitTorrent] "C:\bearshare\bittorrent.exe" --force_start_minimized
O4 - HKUS\S-1-5-18\..\Run: [MySpaceIM] C:\Program Files\MySpace\IM\MySpaceIM.exe (User 'SYSTEM')
O4 - HKUS\.DEFAULT\..\Run: [MySpaceIM] C:\Program Files\MySpace\IM\MySpaceIM.exe (User 'Default user')
O8 - Extra context menu item: E&xport to Microsoft Excel - res://C:\PROGRA~1\MICROS~4\OFFICE11\EXCEL.EXE/3000
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\j2re1.4.2_03\bin\npjpi142_03.dll
O9 - Extra 'Tools' menuitem: Sun Java Console - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\j2re1.4.2_03\bin\npjpi142_03.dll
O9 - Extra button: Research - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~4\OFFICE11\REFIEBAR.DLL
O9 - Extra button: (no name) - {CD67F990-D8E9-11d2-98FE-00C0F0318AFE} - (no file)
O9 - Extra button: (no name) - {e2e2dd38-d088-4134-82b7-f2ba38496583} - C:\WINDOWS\Network Diagnostic\xpnetdiag.exe
O9 - Extra 'Tools' menuitem: @xpsp3res.dll,-20001 - {e2e2dd38-d088-4134-82b7-f2ba38496583} - C:\WINDOWS\Network Diagnostic\xpnetdiag.exe
O9 - Extra button: Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe
O9 - Extra 'Tools' menuitem: Windows Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe
O16 - DPF: {4ED9DDF0-7479-4BBE-9335-5A1EDB1D8A21} (McAfee.com Operating System Class) - http://download.mcafee.com/molbin/shared/mcinsctl/4,0,0,101/mcinsctl.cab
O17 - HKLM\System\CCS\Services\Tcpip\..\{9C07F5DC-B6B3-4A48-8128-890059692B54}: NameServer = 202.54.10.2,202.54.29.5
O23 - Service: Apple Mobile Device - Apple, Inc. - C:\Program Files\Common Files\Apple\Mobile Device Support\bin\AppleMobileDeviceService.exe
O23 - Service: Ati HotKey Poller - ATI Technologies Inc. - C:\WINDOWS\system32\Ati2evxx.exe
O23 - Service: Canon Camera Access Library 8 (CCALib8) - Canon Inc. - C:\Program Files\Canon\CAL\CALMAIN.exe
O23 - Service: Creative Labs Licensing Service - Creative Labs - C:\Program Files\Common Files\Creative Labs Shared\Service\CreativeLicensing.exe
O23 - Service: Intel(R) PROSet/Wireless Event Log (EvtEng) - Intel Corporation - C:\Program Files\Intel\Wireless\Bin\EvtEng.exe
O23 - Service: iPod Service - Apple Inc. - C:\Program Files\iPod\bin\iPodService.exe
O23 - Service: MBackMonitor - McAfee - C:\Program Files\McAfee\MBK\MBackMonitor.exe
O23 - Service: McAfee Services (mcmscsvc) - McAfee, Inc. - C:\PROGRA~1\McAfee\MSC\mcmscsvc.exe
O23 - Service: McAfee Network Agent (McNASvc) - McAfee, Inc. - c:\program files\common files\mcafee\mna\mcnasvc.exe
O23 - Service: McAfee Scanner (McODS) - McAfee, Inc. - C:\PROGRA~1\McAfee\VIRUSS~1\mcods.exe
O23 - Service: McAfee Proxy Service (McProxy) - McAfee, Inc. - c:\PROGRA~1\COMMON~1\mcafee\mcproxy\mcproxy.exe
O23 - Service: McAfee Real-time Scanner (McShield) - McAfee, Inc. - C:\PROGRA~1\McAfee\VIRUSS~1\mcshield.exe
O23 - Service: McAfee SystemGuards (McSysmon) - McAfee, Inc. - C:\PROGRA~1\McAfee\VIRUSS~1\mcsysmon.exe
O23 - Service: McAfee Personal Firewall Service (MpfService) - McAfee, Inc. - C:\Program Files\McAfee\MPF\MPFSrv.exe
O23 - Service: NICCONFIGSVC - Dell Inc. - C:\Program Files\Dell\QuickSet\NICCONFIGSVC.exe
O23 - Service: Intel(R) PROSet/Wireless Registry Service (RegSrvc) - Intel Corporation - C:\Program Files\Intel\Wireless\Bin\RegSrvc.exe
O23 - Service: Intel(R) PROSet/Wireless Service (S24EventMonitor) - Intel Corporation  - C:\Program Files\Intel\Wireless\Bin\S24EvMon.exe
O23 - Service: SiteAdvisor Service - Unknown owner - C:\Program Files\SiteAdvisor\6253\SAService.exe
O23 - Service: Intel(R) PROSet/Wireless SSO Service (WLANKEEPER) - Intel(R) Corporation - C:\Program Files\Intel\Wireless\Bin\WLKeeper.exe

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End of file - 8678 bytes

If anybody has a clue to solve this, please reply to this message.

 Anticipating a reply.

Thanks in advance