Grazie mille!!
Non ho ancora provato perchè è scritto in inglese e ho paura di sbagliare.

Logfile of HijackThis v1.99.0
Scan saved at 19.14.36, on 11/09/2005
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\Explorer.EXE
C:\DOCUME~1\MICHELE\IMPOST~1\Temp\Directory temporanea 5 per hijackthis.zip\HijackThis.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Bar = http://arianna.libero.it
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://www.libero.it/
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://www.libero.it
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Window Title = Microsoft Internet Explorer fornito da Libero
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Collegamenti
O2 - BHO: AcroIEHlprObj Class - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\apps\Adobe\Acrobat 5.0\Reader\ActiveX\AcroIEHelper.ocx
O2 - BHO: (no name) - {53707962-6F74-2D53-2644-206D7942484F} - C:\Programmi\Spybot - Search & Destroy\SDHelper.dll
O2 - BHO: CNavExtBho Class - {BDF3E430-B101-42AD-A544-FADC6B084872} - C:\Programmi\Norton AntiVirus\NavShExt.dll
O3 - Toolbar: Norton AntiVirus - {42CDD1BF-3FFB-4238-8AD1-7859DF00B1D6} - C:\Programmi\Norton AntiVirus\NavShExt.dll
O4 - HKLM\..\Run: [ESB] C:\WINDOWS\System32\ESB.exe
O4 - HKLM\..\Run: [PCTVOICE] pctspk.exe
O4 - HKLM\..\Run: [SynTPLpr] C:\Programmi\Synaptics\SynTP\SynTPLpr.exe
O4 - HKLM\..\Run: [SynTPEnh] C:\Programmi\Synaptics\SynTP\SynTPEnh.exe
O4 - HKLM\..\Run: [SiS Tray] C:\WINDOWS\System32\sistray.EXE
O4 - HKLM\..\Run: [SiS KHooker] C:\WINDOWS\System32\khooker.exe
O4 - HKLM\..\Run: [NAV Agent] C:\PROGRA~1\NORTON~1\navapw32.exe
O4 - HKLM\..\Run: [ActivSurf] C:\apps\ActivSurf\4448364\Program\backweb-4448364.exe
O4 - HKLM\..\Run: [Symantec NetDriver Monitor] C:\PROGRA~1\SYMNET~1\SNDMon.exe /Consumer
O4 - HKCU\..\Run: [MSMSGS] "C:\Programmi\Messenger\msmsgs.exe" /background
O4 - HKCU\..\Run: [IncrediMail] C:\PROGRA~1\INCRED~1\bin\IncMail.exe /c
O4 - Global Startup: Microsoft Office.lnk = C:\Programmi\Microsoft Office\Office\OSA9.EXE
O4 - Global Startup: Picture Package Menu.lnk = C:\Documents and Settings\MICHELE\Documenti\Picture Package Menu\SonyTray.exe
O4 - Global Startup: Picture Package VCD Maker.lnk = C:\Documents and Settings\MICHELE\Documenti\Picture Package Applications\Residence.exe
O8 - Extra context menu item: &Add animation to IncrediMail Style Box - C:\PROGRA~1\INCRED~1\bin\resources\WebMenuImg.htm
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
O14 - IERESET.INF: START_PAGE_URL=http://www.libero.it
O16 - DPF: {2B323CD9-50E3-11D3-9466-00A0C9700498} (Yahoo! Audio Conferencing) - http://jcs.chat.dcn.yahoo.com/v45/yacscom.cab
O16 - DPF: {6414512B-B978-451D-A0D8-FCFDF33E833C} (WUWebControl Class) - http://update.microsoft.com/windowsupdate/v6/V5Controls/en/x86/client/wuweb_site.cab?1122656727361
O23 - Service: Servizio Norton AntiVirus Auto-Protect - Symantec Corporation - C:\Programmi\Norton AntiVirus\navapsvc.exe
O23 - Service: ScriptBlocking Service - Symantec Corporation - C:\PROGRA~1\FILECO~1\SYMANT~1\SCRIPT~1\SBServ.exe
O23 - Service: Symantec Network Drivers Service - Symantec Corporation - C:\Programmi\File comuni\Symantec Shared\SNDSrvc.exe