Problème : processeur souvent à 100%

Bonjour,
comme l'indique le titre, j'ai depuis peu un problème récurrent de lenteur avec mon pc. Le problème vient du fait que le processeur sature sans arrêt et est à 100% très souvent.

Je suis allé voir sur le gestionnaire ce qui clochait et j'ai vu une poignée de programmes qui me paraissent suspects :
- csrss.exe (la description où l'on peut lire "executtion" me paraît louche)
- svchost.exe x13 (je pense que ça fait beaucoup quand même)
- taskeng.exe x4 (j'ai cru comprendre que ce programme était aussi souvent la cible de plusieurs infections).

Pour aider au mieux, je vous ai concocté mon rapport le plus récent sur Hijackthis :

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 08:47:09, on 13/12/2010
Platform: Windows Vista SP2 (WinNT 6.00.1906)
MSIE: Internet Explorer v8.00 (8.00.6001.18975)
Boot mode: Normal

Running processes:
C:\Windows\system32\taskeng.exe
C:\Windows\Explorer.EXE
c:\PROGRA~1\mcafee.com\agent\mcagent.exe
C:\Program Files\Synaptics\SynTP\SynTPEnh.exe
C:\Program Files\CyberLink\PowerDVD\PDVDServ.exe
C:\Program Files\Samsung\Samsung Recovery Solution II\WCScheduler.exe
C:\Program Files\iTunes\iTunesHelper.exe
C:\Program Files\ATI Technologies\ATI.ACE\Core-Static\MOM.EXE
C:\Program Files\WIDCOMM\Bluetooth Software\BTTray.exe
C:\Program Files\ATI Technologies\ATI.ACE\Core-Static\CCC.exe
c:\program files\mcafee\msc\mcuimgr.exe
C:\Program Files\Samsung\Samsung Update Plus\SLUTrayNotifier.exe
C:\Windows\system32\Dwm.exe
C:\Users\Geoffrey\Downloads\HiJackThis(2).exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = http://go.microsoft.com/fwlink/?LinkId=54896
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = https://fr.ask.com/?o=14978&l=dis
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http:\\www.samsungcomputer.com
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 Page = http://go.microsoft.com/fwlink/?LinkId=54896
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = http://go.microsoft.com/fwlink/?LinkId=69157
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant = 
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,CustomizeSearch = 
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyOverride = *.local
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = 
O1 - Hosts: ::1 localhost
O2 - BHO: Adobe PDF Reader Link Helper - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Program Files\Adobe\Acrobat 7.0\ActiveX\AcroIEHelper.dll
O2 - BHO: (no name) - {5C255C8A-E604-49b4-9D64-90988571CECB} - (no file)
O2 - BHO: scriptproxy - {7DB2D5A0-7241-4E79-B68D-6309F01C5231} - c:\program files\mcafee\virusscan\scriptcl.dll
O2 - BHO: Programme d'aide de l'Assistant de connexion Windows Live - {9030D464-4C02-4ABF-8ECC-5164760863C6} - C:\Program Files\Common Files\Microsoft Shared\Windows Live\WindowsLiveLogin.dll
O4 - HKLM\..\Run: [Windows Defender] %ProgramFiles%\Windows Defender\MSASCui.exe -hide
O4 - HKLM\..\Run: [SynTPEnh] C:\Program Files\Synaptics\SynTP\SynTPEnh.exe
O4 - HKLM\..\Run: [Play AVStation TV Scheduler] C:\Program Files\Samsung\Play AVStation\TvScheduler.exe
O4 - HKLM\..\Run: [RemoteControl] "C:\Program Files\CyberLink\PowerDVD\PDVDServ.exe"
O4 - HKLM\..\Run: [LanguageShortcut] "C:\Program Files\CyberLink\PowerDVD\Language\Language.exe"
O4 - HKLM\..\Run: [SamsungWInClon] C:\Program Files\Samsung\Samsung Recovery Solution II\WCScheduler.exe
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\QTTask.exe" -atboottime
O4 - HKLM\..\Run: [Malwarebytes Anti-Malware (reboot)] "C:\Program Files\Malwarebytes' Anti-Malware\mbam.exe" /runcleanupscript
O4 - HKLM\..\Run: [iTunesHelper] "C:\Program Files\iTunes\iTunesHelper.exe"
O4 - HKLM\..\Run: [AppleSyncNotifier] C:\Program Files\Common Files\Apple\Mobile Device Support\AppleSyncNotifier.exe
O4 - HKCU\..\Run: [Sidebar] C:\Program Files\Windows Sidebar\sidebar.exe /autoRun
O4 - HKCU\..\Run: [StartCCC] C:\Program Files\ATI Technologies\ATI.ACE\Core-Static\CLIStart.exe
O4 - HKCU\..\Run: [msnmsgr] "C:\Program Files\Windows Live\Messenger\msnmsgr.exe" /background
O4 - HKCU\..\Run: [ISUSPM] "C:\Program Files\Common Files\InstallShield\UpdateService\ISUSPM.exe" -scheduler
O4 - HKCU\..\Run: [RegistryBooster] "D:\Registry\RegistryBooster\launcher.exe" delay 20000 
O4 - Global Startup: BTTray.lnk = ?
O8 - Extra context menu item: E&xporter vers Microsoft Excel - res://C:\PROGRA~1\MICROS~2\Office12\EXCEL.EXE/3000
O9 - Extra button: PokerStars.fr - {90EAE591-7E7E-434a-8E28-ECFD00071806} - C:\Program Files\PokerStars.FR\PokerStarsUpdate.exe
O9 - Extra button: Research - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~2\Office12\REFIEBAR.DLL
O9 - Extra button: @btrez.dll,-4015 - {CCA281CA-C863-46ef-9331-5C8D4460577F} - C:\Program Files\WIDCOMM\Bluetooth Software\btsendto_ie.htm
O9 - Extra 'Tools' menuitem: @btrez.dll,-12650 - {CCA281CA-C863-46ef-9331-5C8D4460577F} - C:\Program Files\WIDCOMM\Bluetooth Software\btsendto_ie.htm
O13 - Gopher Prefix: 
O23 - Service: Apple Mobile Device - Apple Inc. - C:\Program Files\Common Files\Apple\Mobile Device Support\AppleMobileDeviceService.exe
O23 - Service: Ati External Event Utility - ATI Technologies Inc. - C:\Windows\system32\Ati2evxx.exe
O23 - Service: Service Bonjour (Bonjour Service) - Apple Inc. - C:\Program Files\Bonjour\mDNSResponder.exe
O23 - Service: Bluetooth Service (btwdins) - Broadcom Corporation. - C:\Program Files\WIDCOMM\Bluetooth Software\bin\btwdins.exe
O23 - Service: McAfee E-mail Proxy (Emproxy) - McAfee, Inc. - C:\PROGRA~1\COMMON~1\McAfee\EmProxy\emproxy.exe
O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files\Common Files\InstallShield\Driver\1050\Intel 32\IDriverT.exe
O23 - Service: Service de l'iPod (iPod Service) - Apple Inc. - C:\Program Files\iPod\bin\iPodService.exe
O23 - Service: McAfee HackerWatch Service - McAfee, Inc. - C:\Program Files\Common Files\McAfee\HackerWatch\HWAPI.exe
O23 - Service: McAfee Log Manager (McLogManagerService) - McAfee, Inc. - C:\PROGRA~1\McAfee\MSC\mclogsrv.exe
O23 - Service: McAfee Update Manager (mcmispupdmgr) - McAfee, Inc. - C:\PROGRA~1\McAfee\MSC\mcupdmgr.exe
O23 - Service: McAfee Scanner (McODS) - McAfee, Inc. - C:\PROGRA~1\McAfee\VIRUSS~1\mcods.exe
O23 - Service: McAfee Protection Manager (mcpromgr) - McAfee, Inc. - C:\PROGRA~1\McAfee\MSC\mcpromgr.exe
O23 - Service: McAfee Redirector Service (McRedirector) - McAfee, Inc. - c:\PROGRA~1\COMMON~1\mcafee\redirsvc\redirsvc.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 Task Scheduler (mctskshd.exe) - McAfee, Inc. - C:\PROGRA~1\McAfee\MSC\mctskshd.exe
O23 - Service: McAfee User Manager (mcusrmgr) - McAfee, Inc. - C:\PROGRA~1\McAfee\MSC\mcusrmgr.exe
O23 - Service: McAfee Personal Firewall Service (MpfService) - McAfee, Inc. - C:\Program Files\McAfee\MPF\MPFSrv.exe
O23 - Service: Cyberlink RichVideo Service(CRVS) (RichVideo) - Unknown owner - C:\Program Files\CyberLink\Shared Files\RichVideo.exe
O23 - Service: Samsung Update Plus - Unknown owner - C:\Program Files\Samsung\Samsung Update Plus\SLUBackgroundService.exe

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Toute aide est évidemment la bienvenue.
Amicalement