Erreur lecture disque + PC lent

bonjour
depuis une semaine j'ai un probleme avec mon pc (window xp)
au demarrage il m'indique une erreur lecture disque et me dit de redemarer en insistant et au bout de nombreux redemarrage il finit par marcher sans message d'erreur tout en etant tres lent.
est-ce que ce peut etre un probleme lie au disque dur (cela m'etonnerais vu qu'il fonctionne certaine fois) ou un virrus peut etre ?

merci de bien vouloir m'aider
j'ai lance le log de Hijackthis et voila le resultat
Logfile of HijackThis v1.99.1
Scan saved at 13:38:52, on 22/06/2006
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:\Program Files\Fichiers communs\Symantec Shared\ccPwdSvc.exe
C:\WINDOWS\Explorer.EXE
C:\Program Files\Fichiers communs\Symantec Shared\ccSetMgr.exe
C:\Program Files\Norton AntiVirus\navapsvc.exe
C:\WINDOWS\system32\nvsvc32.exe
C:\Program Files\Norton AntiVirus\SAVScan.exe
C:\Program Files\Fichiers communs\Symantec Shared\SNDSrvc.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\RUNDLL32.EXE
C:\Program Files\WinPoET Broadband Connection\WrOS.EXE
C:\Program Files\Fichiers communs\Real\Update_OB\realsched.exe
C:\Program Files\MSN Messenger\msnmsgr.exe
C:\Program Files\Fichiers communs\Symantec Shared\ccEvtMgr.exe
C:\Program Files\Nikon\PictureProject\NkbMonitor.exe
C:\Program Files\Fichiers communs\Symantec Shared\Security Center\SymWSC.exe
C:\Program Files\Ulead Systems\Ulead Photo Express 2 SE\CalCheck.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\Documents and Settings\Caiveau\Bureau\HijackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = https://www.google.fr/?gws_rd=ssl
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Window Title = Microsoft Internet Explorer fourni par modulo Net
O2 - BHO: SSVHelper Class - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Program Files\Java\jre1.5.0_06\bin\ssv.dll
O2 - BHO: NAV Helper - {BDF3E430-B101-42AD-A544-FADC6B084872} - C:\Program Files\Norton AntiVirus\NavShExt.dll
O3 - Toolbar: Norton AntiVirus - {42CDD1BF-3FFB-4238-8AD1-7859DF00B1D6} - C:\Program Files\Norton AntiVirus\NavShExt.dll
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: [MSConfig] C:\WINDOWS\PCHealth\HelpCtr\Binaries\MSConfig.exe /auto
O4 - HKLM\..\Run: [PE2CKFNT SE] C:\Program Files\Ulead Systems\Ulead Photo Express 2 SE\ChkFont.exe
O4 - HKLM\..\Run: [TkBellExe] "C:\Program Files\Fichiers communs\Real\Update_OB\realsched.exe" -osboot
O4 - HKLM\..\Run: [UserFaultCheck] %systemroot%\system32\dumprep 0 -u
O4 - HKCU\..\Run: [msnmsgr] "C:\Program Files\MSN Messenger\msnmsgr.exe" /background
O4 - Startup: Norton AntiVirus 2004.lnk = C:\Program Files\Fichiers communs\Symantec Shared\NMain.exe
O4 - Startup: Raccourci vers CCAPP.lnk = C:\Program Files\Fichiers communs\Symantec Shared\CCAPP.EXE
O4 - Global Startup: Adobe Gamma Loader.lnk = C:\Program Files\Fichiers communs\Adobe\Calibration\Adobe Gamma Loader.exe
O4 - Global Startup: Microsoft Office.lnk = C:\Program Files\Microsoft Office\Office\OSA9.EXE
O4 - Global Startup: NkbMonitor.exe.lnk = C:\Program Files\Nikon\PictureProject\NkbMonitor.exe
O4 - Global Startup: Photo Express Calendar Checker SE.lnk = C:\Program Files\Ulead Systems\Ulead Photo Express 2 SE\CalCheck.exe
O8 - Extra context menu item: &Télécharger avec NetTransport - C:\Program Files\Xi\NetTransport 2\NTAddLink.html
O8 - Extra context menu item: E&xporter vers Microsoft Excel - res://C:\PROGRA~1\MICROS~3\Office10\EXCEL.EXE/3000
O8 - Extra context menu item: Tout t&élécharger avec NetTransport - C:\Program Files\Xi\NetTransport 2\NTAddList.html
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.5.0_06\bin\ssv.dll
O9 - Extra 'Tools' menuitem: Console Java (Sun) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.5.0_06\bin\ssv.dll
O9 - Extra button: Run WinHTTrack - {36ECAF82-3300-8F84-092E-AFF36D6C7040} - C:\Program Files\WinHTTrack\WinHTTrackIEBar.dll
O9 - Extra 'Tools' menuitem: Launch WinHTTrack - {36ECAF82-3300-8F84-092E-AFF36D6C7040} - C:\Program Files\WinHTTrack\WinHTTrackIEBar.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: {00B71CFB-6864-4346-A978-C0A14556272C} (Checkers Class) - http://messenger.zone.msn.com/binary/msgrchkr.cab31267.cab
O16 - DPF: {1754A1BA-A1DF-4F10-B199-AA55AA1A120F} (InstallerBehaviorFactory Class) - https://www.msn.com/fr-fr/
O16 - DPF: {1F2F4C9E-6F09-47BC-970D-3C54734667FE} (LSSupCtl Class) - https://support.norton.com/sp/en/us/home/current/info
O16 - DPF: {2BC66F54-93A8-11D3-BEB6-00105AA9B6AE} (Symantec AntiVirus scanner) - http://security.symantec.com/sscv6/SharedContent/vc/bin/AvSniff.cab
O16 - DPF: {4C39376E-FA9D-4349-BACC-D305C1750EF3} (EPUImageControl Class) - http://tools.ebayimg.com/eps/wl/activex/EPUWALControl_v1-0-3-24.cab
O16 - DPF: {644E432F-49D3-41A1-8DD5-E099162EEEC5} (Symantec RuFSI Utility Class) - http://security.symantec.com/sscv6/SharedContent/common/bin/cabsa.cab
O16 - DPF: {74D05D43-3236-11D4-BDCD-00C04F9A3B61} (HouseCall Control) - https://www.trendmicro.com/en_us/forHome/products/housecall.html
O16 - DPF: {8E0D4DE5-3180-4024-A327-4DFAD1796A8D} (MessengerStatsClient Class) - http://messenger.zone.msn.com/binary/MessengerStatsClient.cab31267.cab
O16 - DPF: {C5E28B9D-0A68-4B50-94E9-E8F6B4697514} (NsvPlayX Control) - http://www.nullsoft.com/nsv/embed/nsvplayx_vp3_mp3.cab
O16 - DPF: {CE28D5D2-60CF-4C7D-9FE8-0F47A3308078} (ActiveDataInfo Class) - https://support.norton.com/sp/en/us/home/current/info
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\Fichiers communs\Adobe Systems Shared\Service\Adobelmsvc.exe
O23 - Service: Symantec Event Manager (ccEvtMgr) - Symantec Corporation - C:\Program Files\Fichiers communs\Symantec Shared\ccEvtMgr.exe
O23 - Service: Symantec Password Validation (ccPwdSvc) - Symantec Corporation - C:\Program Files\Fichiers communs\Symantec Shared\ccPwdSvc.exe
O23 - Service: Symantec Settings Manager (ccSetMgr) - Symantec Corporation - C:\Program Files\Fichiers communs\Symantec Shared\ccSetMgr.exe
O23 - Service: Service Norton AntiVirus Auto-Protect (navapsvc) - Symantec Corporation - C:\Program Files\Norton AntiVirus\navapsvc.exe
O23 - Service: NVIDIA Display Driver Service (NVSvc) - NVIDIA Corporation - C:\WINDOWS\system32\nvsvc32.exe
O23 - Service: SAVScan - Symantec Corporation - C:\Program Files\Norton AntiVirus\SAVScan.exe
O23 - Service: ScriptBlocking Service (SBService) - Symantec Corporation - C:\PROGRA~1\FICHIE~1\SYMANT~1\SCRIPT~1\SBServ.exe
O23 - Service: Symantec Network Drivers Service (SNDSrvc) - Symantec Corporation - C:\Program Files\Fichiers communs\Symantec Shared\SNDSrvc.exe
O23 - Service: SymWMI Service (SymWSC) - Symantec Corporation - C:\Program Files\Fichiers communs\Symantec Shared\Security Center\SymWSC.exe
O23 - Service: WinPPPoverEthernet - iVasion, a Routerware Company - C:\Program Files\WinPoET Broadband Connection\WrOS.EXE

merci de m'aider