Salut Nick,
Un bon mois de vacances et les idées claires m'ont permis de supprimer l'entrée de registre ISTBar...
J'ai regardé le problème avec un oeil reposé

et je me suis rapidement aperçu que j'essayais de supprimer cette clé avec un compte qui n'avait pas les droits. Je me suis donc recréé le compte sur lequel il y avait eu l'infection et j'ai pu la supprimer avec regedit.
J'ai repassé Spybot et Adaware et plus rien n'est détecté.
Je te joins la log de HijackThis pour que tu me confirmes que mon ordinateur semble propre.
Amicalement.
Logfile of HijackThis v1.99.1
Scan saved at 14:17:03, on 10/09/2005
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:\PROGRA~1\mcafee.com\vso\mcvsrte.exe
C:\WINDOWS\system32\pctspk.exe
C:\WINDOWS\System32\svchost.exe
C:\Program Files\UPHClean\uphclean.exe
C:\WINDOWS\system32\svchost.exe
c:\PROGRA~1\mcafee.com\vso\mcshield.exe
C:\WINDOWS\Explorer.EXE
C:\PROGRA~1\mcafee.com\vso\mcvsshld.exe
C:\PROGRA~1\mcafee.com\agent\mcagent.exe
c:\progra~1\mcafee.com\vso\mcvsescn.exe
C:\PROGRA~1\mcafee.com\agent\McUpdate.exe
D:\Applications Windows\CyberLink\PowerDVD\PDVDServ.exe
C:\WINDOWS\System32\spool\DRIVERS\W32X86\3\E_S4I0S2.EXE
D:\Program Files\Hewlett-Packard\HP Share-to-Web\hpgs2wnd.exe
D:\Applications Windows\Microsoft Money\System\mnyexpr.exe
C:\Program Files\Messenger\msmsgs.exe
D:\Program Files\Hewlett-Packard\HP Share-to-Web\hpgs2wnf.exe
c:\progra~1\mcafee.com\vso\mcvsftsn.exe
D:\Protection ordinateur\hijackthis\HijackThis.exe
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page =
http://login.aliceadsl.fr/default.php
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Liens
O2 - BHO: Yahoo! Companion BHO - {02478D38-C3F9-4efb-9B51-7695ECA05670} - C:\Program Files\Yahoo!\Companion\Installs\cpn\ycomp5_5_5_0.dll (file missing)
O2 - BHO: AcroIEHlprObj Class - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - D:\Applications Windows\Adobe\Acrobat 7.0\ActiveX\AcroIEHelper.dll
O2 - BHO: (no name) - {243B17DE-77C7-46BF-B94B-0B5F309A0E64} - D:\Applications Windows\Microsoft Money\System\mnyside.dll
O2 - BHO: (no name) - {53707962-6F74-2D53-2644-206D7942484F} - D:\APPLIC~3\SPYBOT~1\SDHelper.dll
O2 - BHO: EpsonToolBandKicker Class - {E99421FB-68DD-40F0-B4AC-B7027CAE2F1A} - C:\Program Files\EPSON\EPSON Web-To-Page\EPSON Web-To-Page.dll
O2 - BHO: (no name) - {FDD3B846-8D59-4ffb-8758-209B6AD74ACC} - (no file)
O3 - Toolbar: McAfee VirusScan - {BA52B914-B692-46c4-B683-905236F6F655} - c:\progra~1\mcafee.com\vso\mcvsshl.dll
O3 - Toolbar: Yahoo! Companion - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - C:\Program Files\Yahoo!\Companion\Installs\cpn\ycomp5_5_5_0.dll (file missing)
O3 - Toolbar: EPSON Web-To-Page - {EE5D279F-081B-4404-994D-C6B60AAEBA6D} - C:\Program Files\EPSON\EPSON Web-To-Page\EPSON Web-To-Page.dll
O4 - HKLM\..\Run: [NeroCheck] C:\WINDOWS\system32\NeroCheck.exe
O4 - HKLM\..\Run: [VSOCheckTask] "c:\PROGRA~1\mcafee.com\vso\mcmnhdlr.exe" /checktask
O4 - HKLM\..\Run: [VirusScan Online] "c:\PROGRA~1\mcafee.com\vso\mcvsshld.exe"
O4 - HKLM\..\Run: [MCAgentExe] c:\PROGRA~1\mcafee.com\agent\mcagent.exe
O4 - HKLM\..\Run: [MCUpdateExe] C:\PROGRA~1\mcafee.com\agent\McUpdate.exe
O4 - HKLM\..\Run: [RemoteControl] "D:\Applications Windows\CyberLink\PowerDVD\PDVDServ.exe"
O4 - HKLM\..\Run: [EPSON Stylus C66 Series] C:\WINDOWS\System32\spool\DRIVERS\W32X86\3\E_S4I0S2.EXE /P23 "EPSON Stylus C66 Series" /O6 "USB001" /M "Stylus C66"
O4 - HKLM\..\Run: [Share-to-Web Namespace Daemon] D:\Program Files\Hewlett-Packard\HP Share-to-Web\hpgs2wnd.exe
O4 - HKLM\..\Run: [MessengerPlus3] "C:\Program Files\MSN Messenger\Nouveau dossier\MsgPlus.exe"
O4 - HKCU\..\Run: [MoneyAgent] "D:\Applications Windows\Microsoft Money\System\mnyexpr.exe"
O4 - HKCU\..\Run: [MSMSGS] "C:\Program Files\Messenger\msmsgs.exe" /background
O4 - Global Startup: Lancement rapide d'Adobe Reader.lnk = D:\Applications Windows\Adobe\Acrobat 7.0\Reader\reader_sl.exe
O4 - Global Startup: Microsoft Office.lnk = D:\Applications Windows\Microsoft Office\Office10\OSA.EXE
O8 - Extra context menu item: E&xporter vers Microsoft Excel -
res://D:\APPLIC~1\MICROS~1\Office10\EXCEL.EXE/3000
O9 - Extra button: MoneySide - {E023F504-0C5A-4750-A1E7-A9046DEA8A21} - D:\Applications Windows\Microsoft Money\System\mnyside.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
O12 - Plugin for .mid: C:\Program Files\Internet Explorer\PLUGINS\npqtplugin2.dll
O16 - DPF: RaptisoftGameLoader -
http://www.miniclip.com/hamsterball/rap ... loader.cab
O16 - DPF: teleir_cert -
https://static.ir.dgi.minefi.gouv.fr/se ... r_cert.cab
O16 - DPF: {00B71CFB-6864-4346-A978-C0A14556272C} (Checkers Class) -
http://messenger.zone.msn.com/binary/ms ... b31267.cab
O16 - DPF: {14B87622-7E19-4EA8-93B3-97215F77A6BC} (MessengerStatsClient Class) -
http://messenger.zone.msn.com/binary/Me ... b31267.cab
O16 - DPF: {17492023-C23A-453E-A040-C7C580BBF700} (Windows Genuine Advantage Validation Tool) -
http://go.microsoft.com/fwlink/?linkid= ... lcid=0x409
O16 - DPF: {2917297F-F02B-4B9D-81DF-494B6333150B} (Minesweeper Flags Class) -
http://messenger.zone.msn.com/binary/Mi ... b31267.cab
O16 - DPF: {4C39376E-FA9D-4349-BACC-D305C1750EF3} (EPUImageControl Class) -
http://tools.ebayimg.com/eps/wl/activex ... 0-3-24.cab
O16 - DPF: {4ED9DDF0-7479-4BBE-9335-5A1EDB1D8A21} (McAfee.com Operating System Class) -
http://bin.mcafee.com/molbin/shared/mci ... insctl.cab
O16 - DPF: {8E0D4DE5-3180-4024-A327-4DFAD1796A8D} (MessengerStatsClient Class) -
http://messenger.zone.msn.com/binary/Me ... b31267.cab
O16 - DPF: {B38870E4-7ECB-40DA-8C6A-595F0A5519FF} (MsnMessengerSetupDownloadControl Class) -
http://messenger.msn.com/download/msnme ... loader.cab
O16 - DPF: {B8BE5E93-A60C-4D26-A2DC-220313175592} (ZoneIntro Class) -
http://messenger.zone.msn.com/binary/ZI ... b31267.cab
O16 - DPF: {BCC0FF27-31D9-4614-A68E-C18E1ADA4389} (DwnldGroupMgr Class) -
http://bin.mcafee.com/molbin/shared/mcg ... cgdmgr.cab
O16 - DPF: {D27CDB6E-AE6D-11CF-96B8-444553540000} (Shockwave Flash Object) -
https://download.macromedia.com/pub/sho ... wflash.cab
O20 - AppInit_DLLs: MsgPlusLoader.dll
O23 - Service: McAfee.com McShield (McShield) - Unknown owner - c:\PROGRA~1\mcafee.com\vso\mcshield.exe
O23 - Service: McAfee SecurityCenter Update Manager (mcupdmgr.exe) - McAfee, Inc - C:\PROGRA~1\McAfee.com\Agent\mcupdmgr.exe
O23 - Service: McAfee.com VirusScan Online Realtime Engine (MCVSRte) - Networks Associates Technology, Inc - c:\PROGRA~1\mcafee.com\vso\mcvsrte.exe
O23 - Service: PCTEL Speaker Phone (Pctspk) - PCtel, Inc. - C:\WINDOWS\system32\pctspk.exe