My PC is running very slow recently. Task manager shows CPU usage at maximum, even with no applications running. Have not loaded any new software. HJT log attached. Can you help?

Logfile of HijackThis v1.99.1
Scan saved at 12:22:25 AM, on 11/10/2006
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v6.00 SP2 (6.00.2900.2180)

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\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\spoolsv.exe
C:\WINDOWS\Explorer.EXE
C:\Program Files\Common Files\InstallShield\UpdateService\issch.exe
C:\WINDOWS\system32\ctfmon.exe
C:\WINDOWS\system32\nvsvc32.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\WgaTray.exe
C:\WINDOWS\system32\wuauclt.exe
C:\WINDOWS\system32\wscntfy.exe
C:\WINDOWS\system32\wuauclt.exe
C:\Hijackthis\HijackThis.exe

O2 - BHO: AcroIEHlprObj Class - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Program Files\Adobe\Adobe Acrobat 6.0\Acrobat\ActiveX\AcroIEHelper.dll
O2 - BHO: AcroIEToolbarHelper Class - {AE7CD045-E861-484f-8273-0445EE161910} - C:\Program Files\Adobe\Adobe Acrobat 6.0\Acrobat\AcroIEFavClient.dll
O3 - Toolbar: Adobe PDF - {47833539-D0C5-4125-9FA8-0819E2EAAC93} - C:\Program Files\Adobe\Adobe Acrobat 6.0\Acrobat\AcroIEFavClient.dll
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\qttask.exe" -atboottime
O4 - HKLM\..\Run: [MCCInstall] D:\Intro\AA\MCCInstall\English\MCCInstall.exe -Step=9 -Settings
O4 - HKLM\..\Run: [SoundMan] SOUNDMAN.EXE
O4 - HKLM\..\Run: [ISUSPM Startup] "C:\Program Files\Common Files\InstallShield\UpdateService\isuspm.exe" -startup
O4 - HKLM\..\Run: [ISUSScheduler] "C:\Program Files\Common Files\InstallShield\UpdateService\issch.exe" -start
O4 - HKLM\..\Run: [Zone Labs Client] "C:\Program Files\Zone Labs\ZoneAlarm\zlclient.exe"
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\system32\NvCpl.dll,NvStartup
O4 - HKLM\..\Run: [nwiz] nwiz.exe /install
O4 - HKLM\..\Run: [NvMediaCenter] RUNDLL32.EXE C:\WINDOWS\system32\NvMcTray.dll,NvTaskbarInit
O4 - HKLM\..\Run: [KernelFaultCheck] %systemroot%\system32\dumprep 0 -k
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O8 - Extra context menu item: E&xport to Microsoft Excel - res://C:\PROGRA~1\MICROS~2\OFFICE11\EXCEL.EXE/3000
O9 - Extra button: Research - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~2\OFFICE11\REFIEBAR.DLL
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: {2BC66F54-93A8-11D3-BEB6-00105AA9B6AE} (Symantec AntiVirus scanner) - http://security.symantec.com/sscv6/SharedC…bin/AvSniff.cab
O16 - DPF: {6414512B-B978-451D-A0D8-FCFDF33E833C} (WUWebControl Class) - http://v5.windowsupdate.microsoft.com/v5co…b?1102557510044
O16 - DPF: {644E432F-49D3-41A1-8DD5-E099162EEEC5} (Symantec RuFSI Utility Class) - http://security.symantec.com/sscv6/SharedC…n/bin/cabsa.cab
O16 - DPF: {6E32070A-766D-4EE6-879C-DC1FA91D2FC3} (MUWebControl Class) - http://update.microsoft.com/microsoftupdat…b?1122225663093
O16 - DPF: {8E0D4DE5-3180-4024-A327-4DFAD1796A8D} (MessengerStatsClient Class) - http://messenger.zone.msn.com/binary/Messe…StatsClient.cab
O18 - Protocol: msnim - {828030A1-22C1-4009-854F-8E305202313F} - "C:\PROGRA~1\MSNMES~1\msgrapp.dll" (file missing)
O20 - Winlogon Notify: WgaLogon - C:\WINDOWS\SYSTEM32\WgaLogon.dll
O23 - Service: Adobe LM Service - Unknown owner - C:\Program Files\Common Files\Adobe Systems Shared\Service\Adobelmsvc.exe
O23 - Service: CA ISafe (CAISafe) - Computer Associates International, Inc. - C:\WINDOWS\system32\ZoneLabs\isafe.exe
O23 - Service: NVIDIA Display Driver Service (NVSvc) - NVIDIA Corporation - C:\WINDOWS\system32\nvsvc32.exe
O23 - Service: TrueVector Internet Monitor (vsmon) - Zone Labs, LLC - C:\WINDOWS\system32\ZoneLabs\vsmon.exe