Pc ralenti... Virus ?

Bonjour,

Depuis quelques temps, mon ordinateur a un comportement "bizarre" : ralentissement, freeze d'écran,... je me demande si il n'y aurait pas un virus dessus.

Voici mon rapport Hijackthis :

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 09:29:30, on 17/04/2011
Platform: Unknown Windows (WinNT 6.01.3504)
MSIE: Internet Explorer v8.00 (8.00.7600.16766)
Boot mode: Normal

Running processes:
C:\Program Files (x86)\Common Files\Microsoft Shared\Ink\TabTip32.exe
C:\Program Files (x86)\Bamboo Dock\Bamboo Dock\Bamboo Dock.exe
C:\Users\user\AppData\Local\Google\Update\1.2.183.39\GoogleCrashHandler.exe
C:\Program Files (x86)\Renesas Electronics\USB 3.0 Host Controller Driver\Application\nusb3mon.exe
C:\Program Files (x86)\Canon\Canon IJ Network Scan Utility\CNMNSUT.EXE
C:\Program Files (x86)\Bamboo Dock\BambooCore.exe
C:\Program Files (x86)\Common Files\Java\Java Update\jusched.exe
C:\Program Files (x86)\Adobe\Reader 9.0\Reader\reader_sl.exe
C:\Program Files\AVAST Software\Avast\AvastUI.exe
E:\Documents\HiJackThis\HiJackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://google.fr/
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant = about:blank
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,CustomizeSearch =
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Local Page = C:\Windows\SysWOW64\blank.htm
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName =
F2 - REG:system.ini: UserInit=C:\Windows\SysWOW64\Userinit.exe,
O2 - BHO: AcroIEHelperStub - {18DF081C-E8AD-4283-A596-FA578C2EBDC3} - C:\Program Files (x86)\Common Files\Adobe\Acrobat\ActiveX\AcroIEHelperShim.dll
O2 - BHO: Groove GFS Browser Helper - {72853161-30C5-4D22-B7F9-0BBC1D38A37E} - C:\PROGRA~2\MICROS~1\Office14\GROOVEEX.DLL
O2 - BHO: avast! WebRep - {8E5E2654-AD2D-48bf-AC2D-D17F00898D06} - C:\Program Files\AVAST Software\Avast\aswWebRepIE.dll
O2 - BHO: Programme d'aide de l'Assistant de connexion Windows Live ID - {9030D464-4C02-4ABF-8ECC-5164760863C6} - C:\Program Files (x86)\Common Files\Microsoft Shared\Windows Live\WindowsLiveLogin.dll
O2 - BHO: Windows Live Messenger Companion Helper - {9FDDE16B-836F-4806-AB1F-1455CBEFF289} - C:\Program Files (x86)\Windows Live\Companion\companioncore.dll
O2 - BHO: URLRedirectionBHO - {B4F3A835-0E21-4959-BA22-42B3008E02FF} - C:\PROGRA~2\MICROS~1\Office14\URLREDIR.DLL
O2 - BHO: Java(tm) Plug-In 2 SSV Helper - {DBC80044-A445-435b-BC74-9C25C1C588A9} - C:\Program Files (x86)\Java\jre6\bin\jp2ssv.dll
O3 - Toolbar: avast! WebRep - {8E5E2654-AD2D-48bf-AC2D-D17F00898D06} - C:\Program Files\AVAST Software\Avast\aswWebRepIE.dll
O4 - HKLM\..\Run: [NUSB3MON] "C:\Program Files (x86)\Renesas Electronics\USB 3.0 Host Controller Driver\Application\nusb3mon.exe"
O4 - HKLM\..\Run: [StartCCC] "C:\Program Files (x86)\ATI Technologies\ATI.ACE\Core-Static\CLIStart.exe" MSRun
O4 - HKLM\..\Run: [ATICustomerCare] "C:\Program Files (x86)\ATI\ATICustomerCare\ATICustomerCare.exe"
O4 - HKLM\..\Run: [IJNetworkScanUtility] C:\Program Files (x86)\Canon\Canon IJ Network Scan Utility\CNMNSUT.EXE
O4 - HKLM\..\Run: [BambooCore] C:\Program Files (x86)\Bamboo Dock\BambooCore.exe
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Program Files (x86)\Common Files\Java\Java Update\jusched.exe"
O4 - HKLM\..\Run: [Adobe Reader Speed Launcher] "C:\Program Files (x86)\Adobe\Reader 9.0\Reader\Reader_sl.exe"
O4 - HKLM\..\Run: [Adobe ARM] "C:\Program Files (x86)\Common Files\Adobe\ARM\1.0\AdobeARM.exe"
O4 - HKLM\..\Run: [avast] "C:\Program Files\AVAST Software\Avast\avastUI.exe" /nogui
O4 - HKCU\..\Run: [Google Update] "C:\Users\user\AppData\Local\Google\Update\GoogleUpdate.exe" /c
O4 - HKCU\..\Run: [Sidebar] C:\Program Files\Windows Sidebar\sidebar.exe /autoRun
O4 - HKCU\..\Run: [Bamboo Dock] "C:\Program Files (x86)\Bamboo Dock\Bamboo Dock\Bamboo Dock.exe"
O4 - HKUS\S-1-5-19\..\Run: [Sidebar] %ProgramFiles%\Windows Sidebar\Sidebar.exe /autoRun (User 'SERVICE LOCAL')
O4 - HKUS\S-1-5-19\..\RunOnce: [mctadmin] C:\Windows\System32\mctadmin.exe (User 'SERVICE LOCAL')
O4 - HKUS\S-1-5-20\..\Run: [Sidebar] %ProgramFiles%\Windows Sidebar\Sidebar.exe /autoRun (User 'SERVICE RÉSEAU')
O4 - HKUS\S-1-5-20\..\RunOnce: [mctadmin] C:\Windows\System32\mctadmin.exe (User 'SERVICE RÉSEAU')
O8 - Extra context menu item: E&xporter vers Microsoft Excel - res://C:\PROGRA~1\MICROS~1\Office14\EXCEL.EXE/3000
O9 - Extra button: @C:\Program Files (x86)\Windows Live\Companion\companionlang.dll,-600 - {0000036B-C524-4050-81A0-243669A86B9F} - C:\Program Files (x86)\Windows Live\Companion\companioncore.dll
O10 - Unknown file in Winsock LSP: c:\program files (x86)\common files\microsoft shared\windows live\wlidnsp.dll
O10 - Unknown file in Winsock LSP: c:\program files (x86)\common files\microsoft shared\windows live\wlidnsp.dll
O13 - Gopher Prefix:
O18 - Protocol: skype4com - {FFC8B962-9B40-4DFF-9458-1830C7DD7F5D} - C:\PROGRA~2\COMMON~1\Skype\SKYPE4~1.DLL
O18 - Protocol: wlpg - {E43EF6CD-A37A-4A9B-9E6F-83F89B8E6324} - C:\Program Files (x86)\Windows Live\Photo Gallery\AlbumDownloadProtocolHandler.dll
O18 - Filter hijack: text/xml - {807573E5-5146-11D5-A672-00B0D022E945} - C:\Program Files (x86)\Common Files\Microsoft Shared\OFFICE14\MSOXMLMF.DLL
O23 - Service: Adobe Active File Monitor V8 (AdobeActiveFileMonitor8.0) - Adobe Systems Incorporated - C:\Program Files (x86)\Adobe\Elements Organizer 8.0\PhotoshopElementsFileAgent.exe
O23 - Service: @%SystemRoot%\system32\Alg.exe,-112 (ALG) - Unknown owner - C:\Windows\System32\alg.exe (file missing)
O23 - Service: AMD External Events Utility - Unknown owner - C:\Windows\system32\atiesrxx.exe (file missing)
O23 - Service: avast! iAVS4 Control Service (aswUpdSv) - Unknown owner - C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe (file missing)
O23 - Service: avast! Antivirus - AVAST Software - C:\Program Files\AVAST Software\Avast\AvastSvc.exe
O23 - Service: @%SystemRoot%\system32\efssvc.dll,-100 (EFS) - Unknown owner - C:\Windows\System32\lsass.exe (file missing)
O23 - Service: @%systemroot%\system32\fxsresm.dll,-118 (Fax) - Unknown owner - C:\Windows\system32\fxssvc.exe (file missing)
O23 - Service: FLEXnet Licensing Service - Acresso Software Inc. - C:\Program Files (x86)\Common Files\Macrovision Shared\FLEXnet Publisher\FNPLicensingService.exe
O23 - Service: @keyiso.dll,-100 (KeyIso) - Unknown owner - C:\Windows\system32\lsass.exe (file missing)
O23 - Service: @comres.dll,-2797 (MSDTC) - Unknown owner - C:\Windows\System32\msdtc.exe (file missing)
O23 - Service: @%SystemRoot%\System32\netlogon.dll,-102 (Netlogon) - Unknown owner - C:\Windows\system32\lsass.exe (file missing)
O23 - Service: @%systemroot%\system32\psbase.dll,-300 (ProtectedStorage) - Unknown owner - C:\Windows\system32\lsass.exe (file missing)
O23 - Service: ProtexisLicensing - Unknown owner - C:\Windows\SysWOW64\PSIService.exe
O23 - Service: @%systemroot%\system32\Locator.exe,-2 (RpcLocator) - Unknown owner - C:\Windows\system32\locator.exe (file missing)
O23 - Service: @%SystemRoot%\system32\samsrv.dll,-1 (SamSs) - Unknown owner - C:\Windows\system32\lsass.exe (file missing)
O23 - Service: SBSD Security Center Service (SBSDWSCService) - Safer Networking Ltd. - C:\Program Files (x86)\Spybot - Search & Destroy\SDWinSec.exe
O23 - Service: @%SystemRoot%\system32\snmptrap.exe,-3 (SNMPTRAP) - Unknown owner - C:\Windows\System32\snmptrap.exe (file missing)
O23 - Service: @%systemroot%\system32\spoolsv.exe,-1 (Spooler) - Unknown owner - C:\Windows\System32\spoolsv.exe (file missing)
O23 - Service: @%SystemRoot%\system32\sppsvc.exe,-101 (sppsvc) - Unknown owner - C:\Windows\system32\sppsvc.exe (file missing)
O23 - Service: TabletServicePen - Wacom Technology, Corp. - C:\Program Files\Tablet\Pen\Pen_Tablet.exe
O23 - Service: Wacom Consumer Touch Service (TouchServicePen) - Wacom Technology, Corp. - C:\Program Files\Tablet\Pen\Pen_TouchService.exe
O23 - Service: @%SystemRoot%\system32\ui0detect.exe,-101 (UI0Detect) - Unknown owner - C:\Windows\system32\UI0Detect.exe (file missing)
O23 - Service: @%SystemRoot%\system32\vaultsvc.dll,-1003 (VaultSvc) - Unknown owner - C:\Windows\system32\lsass.exe (file missing)
O23 - Service: @%SystemRoot%\system32\vds.exe,-100 (vds) - Unknown owner - C:\Windows\System32\vds.exe (file missing)
O23 - Service: @%systemroot%\system32\vssvc.exe,-102 (VSS) - Unknown owner - C:\Windows\system32\vssvc.exe (file missing)
O23 - Service: @%SystemRoot%\system32\Wat\WatUX.exe,-601 (WatAdminSvc) - Unknown owner - C:\Windows\system32\Wat\WatAdminSvc.exe (file missing)
O23 - Service: @%systemroot%\system32\wbengine.exe,-104 (wbengine) - Unknown owner - C:\Windows\system32\wbengine.exe (file missing)
O23 - Service: @%Systemroot%\system32\wbem\wmiapsrv.exe,-110 (wmiApSrv) - Unknown owner - C:\Windows\system32\wbem\WmiApSrv.exe (file missing)
O23 - Service: @%PROGRAMFILES%\Windows Media Player\wmpnetwk.exe,-101 (WMPNetworkSvc) - Unknown owner - C:\Program Files (x86)\Windows Media Player\wmpnetwk.exe (file missing)