premetto che ho fatto tutto ma non in modalità provvisoria, inoltre tra le strinche di hijack this non ho trovato la seconda che mi avevi detto di eliminare, e in più il "cerca" di windows non ha trovato i due file che dicevi.... detto ciò ti invio il nuovo log:

Logfile of HijackThis v1.99.1
Scan saved at 18.16.48, on 04/04/2007
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\ZoneLabs\vsmon.exe
C:\WINDOWS\Explorer.EXE
C:\WINDOWS\system32\spoolsv.exe
C:\Programmi\Alwil Software\Avast4\aswUpdSv.exe
C:\Programmi\Alwil Software\Avast4\ashServ.exe
C:\Programmi\Grisoft\AVG Anti-Spyware 7.5\guard.exe
C:\Programmi\Alwil Software\Avast4\ashMaiSv.exe
C:\Programmi\Alwil Software\Avast4\ashWebSv.exe
C:\WINDOWS\system32\wscntfy.exe
C:\WINDOWS\SOUNDMAN.EXE
C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
C:\WINDOWS\AGRSMMSG.exe
C:\Programmi\QuickTime\qttask.exe
C:\Programmi\Zone Labs\ZoneAlarm\zlclient.exe
C:\Programmi\Grisoft\AVG Anti-Spyware 7.5\avgas.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Programmi\Messenger\msmsgs.exe
C:\Programmi\MSN Messenger\MsnMsgr.Exe
C:\Programmi\File comuni\Ahead\lib\NMBgMonitor.exe
C:\Programmi\Internet Explorer\IEXPLORE.EXE
C:\Programmi\File comuni\Microsoft Shared\Windows Live\WLLoginProxy.exe
C:\Documents and Settings\daniela\Documenti\Daniela\Hijack This\HijackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://www.google.it/
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Collegamenti
R3 - URLSearchHook: &Yahoo! Toolbar - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - (no file)
O2 - BHO: Supporto di collegamento per Adobe PDF Reader - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Programmi\File comuni\Adobe\Acrobat\ActiveX\AcroIEHelper.dll
O2 - BHO: (no name) - {53707962-6F74-2D53-2644-206D7942484F} - C:\Programmi\Spybot - Search & Destroy\SDHelper.dll
O2 - BHO: (no name) - {7E853D72-626A-48EC-A868-BA8D5E23E045} - (no file)
O2 - BHO: Windows Live Sign-in Helper - {9030D464-4C02-4ABF-8ECC-5164760863C6} - C:\Programmi\File comuni\Microsoft Shared\Windows Live\WindowsLiveLogin.dll
O4 - HKLM\..\Run: [SoundMan] SOUNDMAN.EXE
O4 - HKLM\..\Run: [avast!] C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
O4 - HKLM\..\Run: [Ptipbmf] rundll32.exe ptipbmf.dll,SetWriteCacheMode
O4 - HKLM\..\Run: [NeroFilterCheck] C:\WINDOWS\system32\NeroCheck.exe
O4 - HKLM\..\Run: [AGRSMMSG] AGRSMMSG.exe
O4 - HKLM\..\Run: [QuickTime Task] "C:\Programmi\QuickTime\qttask.exe" -atboottime
O4 - HKLM\..\Run: [ZoneAlarm Client] "C:\Programmi\Zone Labs\ZoneAlarm\zlclient.exe"
O4 - HKLM\..\Run: [!AVG Anti-Spyware] "C:\Programmi\Grisoft\AVG Anti-Spyware 7.5\avgas.exe" /minimized
O4 - HKCU\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\ctfmon.exe
O4 - HKCU\..\Run: [MSMSGS] "C:\Programmi\Messenger\msmsgs.exe" /background
O4 - HKCU\..\Run: [MsnMsgr] "C:\Programmi\MSN Messenger\MsnMsgr.Exe" /background
O4 - HKCU\..\Run: [BgMonitor_{79662E04-7C6C-4d9f-84C7-88D8A56B10AA}] "C:\Programmi\File comuni\Ahead\lib\NMBgMonitor.exe"
O4 - Startup: Adobe Gamma.lnk = C:\Programmi\File comuni\Adobe\Calibration\Adobe Gamma Loader.exe
O4 - Global Startup: Adobe Reader Synchronizer.lnk = C:\Programmi\Adobe\Reader 8.0\Reader\AdobeCollabSync.exe
O4 - Global Startup: Avvio veloce di Adobe Reader.lnk = C:\Programmi\Adobe\Reader 8.0\Reader\reader_sl.exe
O8 - Extra context menu item: E&sporta in Microsoft Excel - res://C:\PROGRA~1\MICROS~2\OFFICE11\EXCEL.EXE/3000
O9 - Extra button: Ricerche - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~2\OFFICE11\REFIEBAR.DLL
O9 - Extra button: Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Programmi\Messenger\msmsgs.exe
O9 - Extra 'Tools' menuitem: Windows Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Programmi\Messenger\msmsgs.exe
O16 - DPF: {2BC66F54-93A8-11D3-BEB6-00105AA9B6AE} (Symantec AntiVirus scanner) - http://security.symantec.com/sscv6/SharedContent/vc/bin/AvSniff.cab
O16 - DPF: {644E432F-49D3-41A1-8DD5-E099162EEEC5} (Symantec RuFSI Utility Class) - http://security.symantec.com/sscv6/SharedContent/common/bin/cabsa.cab
O18 - Protocol: livecall - {828030A1-22C1-4009-854F-8E305202313F} - C:\PROGRA~1\MSNMES~1\MSGRAP~1.DLL
O18 - Protocol: msnim - {828030A1-22C1-4009-854F-8E305202313F} - C:\PROGRA~1\MSNMES~1\MSGRAP~1.DLL
O23 - Service: Adobe LM Service - Adobe Systems - C:\Programmi\File comuni\Adobe Systems Shared\Service\Adobelmsvc.exe
O23 - Service: avast! iAVS4 Control Service (aswUpdSv) - Unknown owner - C:\Programmi\Alwil Software\Avast4\aswUpdSv.exe
O23 - Service: avast! Antivirus - Unknown owner - C:\Programmi\Alwil Software\Avast4\ashServ.exe
O23 - Service: avast! Mail Scanner - Unknown owner - C:\Programmi\Alwil Software\Avast4\ashMaiSv.exe" /service (file missing)
O23 - Service: avast! Web Scanner - Unknown owner - C:\Programmi\Alwil Software\Avast4\ashWebSv.exe" /service (file missing)
O23 - Service: AVG Anti-Spyware Guard - Anti-Malware Development a.s. - C:\Programmi\Grisoft\AVG Anti-Spyware 7.5\guard.exe
O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Programmi\File comuni\InstallShield\Driver\11\Intel 32\IDriverT.exe
O23 - Service: Macromedia Licensing Service - Unknown owner - C:\Programmi\File comuni\Macromedia Shared\Service\Macromedia Licensing.exe
O23 - Service: TrueVector Internet Monitor (vsmon) - Zone Labs, LLC - C:\WINDOWS\system32\ZoneLabs\vsmon.exe


grazie di tutto

una domanda:
ma il file da cercare è
svhost.exe
oppure
svchost.exe
?