Thanks for you help!
Running processes:
C:\WINDOWS\SYSTEM\KERNEL32.DLL
C:\WINDOWS\SYSTEM\MSGSRV32.EXE
C:\WINDOWS\SYSTEM\MPREXE.EXE
C:\WINDOWS\SYSTEM\mmtask.tsk
C:\WINDOWS\SYSTEM\MSTASK.EXE
C:\WINDOWS\EXPLORER.EXE
C:\WINDOWS\TASKMON.EXE
C:\WINDOWS\SYSTEM\SYSTRAY.EXE
C:\WINDOWS\SYSTEM\ATIPTAXX.EXE
C:\WINDOWS\RUNDLL32.EXE
C:\WINDOWS\SYSTEM\SYSMON.EXE
C:\PROGRAMMI\MICROSOFT OFFICE\OFFICE\OSA.EXE
C:\PROGRAMMI\MICROSOFT OFFICE\OFFICE\FINDFAST.EXE
C:\WINDOWS\SYSTEM\RNAAPP.EXE
C:\WINDOWS\SYSTEM\TAPISRV.EXE
C:\WINDOWS\SYSTEM\WMIEXE.EXE
C:\PROGRAMMI\ALICE\ALICE ENTERNET\APP\ENTERNET.EXE
C:\PROGRAMMI\INTERNET EXPLORER\IEXPLORE.EXE
C:\WINDOWS\SYSTEM\PSTORES.EXE
C:\WINDOWS\SYSTEM\DDHELP.EXE
C:\WINDOWS\DESKTOP\HIJACK\HIJACKTHIS.EXE
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Collegamenti
O2 - BHO: AcroIEHlprObj Class - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\PROGRAMMI\ADOBE\ACROBAT 5.0\READER\ACTIVEX\ACROIEHELPER.OCX
O3 - Toolbar: &Radio - {8E718888-423F-11D2-876E-00A0C9082467} - C:\WINDOWS\SYSTEM\MSDXM.OCX
O4 - HKLM\..\Run: [ScanRegistry] C:\WINDOWS\scanregw.exe /autorun
O4 - HKLM\..\Run: [TaskMonitor] C:\WINDOWS\taskmon.exe
O4 - HKLM\..\Run: [SystemTray] SysTray.Exe
O4 - HKLM\..\Run: [LoadPowerProfile] Rundll32.exe powrprof.dll,LoadCurrentPwrScheme
O4 - HKLM\..\Run: [AtiPTA] Atiptaxx.exe
O4 - HKLM\..\Run: [CnxTrApp] rundll32.exe C:\WINDOWS\Pirelli.USB\CnxTrApp.dll,AppEntryA -REG "Pirelli\Access Gateway USB"
O4 - HKLM\..\Run: [Systems] C:\WINDOWS\SYSTEM\sysmon.exe
O4 - HKLM\..\RunServices: [LoadPowerProfile] Rundll32.exe powrprof.dll,LoadCurrentPwrScheme
O4 - HKLM\..\RunServices: [SchedulingAgent] C:\WINDOWS\SYSTEM\mstask.exe
O4 - HKLM\..\RunOnce: [HRZR_PGYFRFFVBA] 8/
O4 - Startup: Avvio Office.lnk = C:\Programmi\Microsoft Office\Office\OSA.EXE
O4 - Startup: Ricerca rapida.lnk = C:\Programmi\Microsoft Office\Office\FINDFAST.EXE
O9 - Extra button: Related - {c95fe080-8f5d-11d2-a20b-00aa003c157a} - C:\WINDOWS\web\related.htm
O9 - Extra 'Tools' menuitem: Show &Related Links - {c95fe080-8f5d-11d2-a20b-00aa003c157a} - C:\WINDOWS\web\related.htm
O12 - Plugin for .avi: C:\PROGRA~1\INTERN~1\PLUGINS\npqtplugin.dll