Ciao
un mio amico mi ha chiesto un aiuto su un problema di mancato avvio del proprio computer in quanto gli chiedeva continuamente di inserire il Disk di avvio e premere enter.
Dopo vari tentativi sono riuscito ad avviarlo e quindi ho fatto prontamente il LOG con HJT
Da analizza vedo parecchi files sospetti, ma chiedo a voi quali di questi dovrebbe fixare
Grazie a chi vorra' darmi il suo parere

Logfile of HijackThis v1.99.1
Scan saved at 15.09.25, on 04/11/2010
Platform: Windows XP SP3 (WinNT 5.01.2600)
MSIE: Internet Explorer v8.00 (8.00.6001.18702)

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:\Programmi\Alwil Software\Avast5\AvastSvc.exe
C:\WINDOWS\Explorer.EXE
C:\Programmi\Alwil Software\Avast5\avastUI.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Programmi\MSN Messenger\MsnMsgr.Exe
C:\Programmi\File comuni\Ahead\Lib\NMBgMonitor.exe
C:\Programmi\Picasa2\PicasaMediaDetector.exe
C:\Programmi\Messenger\msmsgs.exe
C:\Programmi\Skype\Phone\Skype.exe
C:\Programmi\File comuni\Ahead\Lib\NMIndexStoreSvr.exe
C:\WINDOWS\system32\spoolsv.exe
C:\Programmi\File comuni\Microsoft Shared\VS7DEBUG\MDM.EXE
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\system32\wbem\wmiapsrv.exe
C:\Programmi\File comuni\Ahead\Lib\NMIndexingService.exe
D:\PROGRAMMI SCARICATI\HijackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://www.
libero.it/
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http:
//go.microsoft.com/fwlink/?LinkId=69157
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http:
//go.microsoft.com/fwlink/?LinkId=54896
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = http://go.
microsoft.com/fwlink/?LinkId=54896
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = http://go.
microsoft.com/fwlink/?LinkId=69157
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName =
Collegamenti
R3 - URLSearchHook: Yahoo! Toolbar con blocco Pop-Up - {EF99BD32-C1FB-11D2-
892F-0090271D4F88} - C:\Programmi\Yahoo!\Companion\Installs\cpn\yt.dll
O2 - BHO: Yahoo! Toolbar Helper - {02478D38-C3F9-4EFB-9B51-7695ECA05670} - C:
\Programmi\Yahoo!\Companion\Installs\cpn\yt.dll
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)
O3 - Toolbar: Yahoo! Toolbar con blocco Pop-Up - {EF99BD32-C1FB-11D2-892F-
0090271D4F88} - C:\Programmi\Yahoo!\Companion\Installs\cpn\yt.dll
O4 - HKLM\..\Run: [NeroFilterCheck] C:\Programmi\File
comuni\Ahead\Lib\NeroCheck.exe
O4 - HKLM\..\Run: [Adobe Reader Speed Launcher] "C:\Programmi\Adobe\Reader 8.0
\Reader\Reader_sl.exe"
O4 - HKLM\..\Run: [avast5] "C:\Programmi\Alwil Software\Avast5\avastUI.exe"
/nogui
O4 - HKCU\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\ctfmon.exe
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 - HKCU\..\Run: [Picasa Media Detector] C:
\Programmi\Picasa2\PicasaMediaDetector.exe
O4 - HKCU\..\Run: [MSMSGS] "C:\Programmi\Messenger\msmsgs.exe" /background
O4 - HKCU\..\Run: [Skype] "C:\Programmi\Skype\Phone\Skype.exe" /nosplash
/minimized
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: (no name) - {e2e2dd38-d088-4134-82b7-f2ba38496583} - %
windir%\Network Diagnostic\xpnetdiag.exe (file missing)
O9 - Extra 'Tools' menuitem: @xpsp3res.dll,-20001 - {e2e2dd38-d088-4134-82b7-
f2ba38496583} - %windir%\Network Diagnostic\xpnetdiag.exe (file missing)
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
O11 - Options group: [INTERNATIONAL] International
O16 - DPF: {30528230-99f7-4bb4-88d8-fa1d4f56a2ab} (YInstStarter Class) - C:
\Programmi\Yahoo!\Common\yinsthelper.dll
O16 - DPF: {6414512B-B978-451D-A0D8-FCFDF33E833C} (WUWebControl Class) - http:
//www.update.microsoft.com/windowsupdate/v6/V5Controls/en/x86/client/wuweb_site.
cab?1224685707921
O17 - HKLM\System\CCS\Services\Tcpip\..\{6AA7AB2A-CE8A-450E-BAF8-
D6E14E7BECA5}: NameServer = 193.70.152.15,193.70.152.25
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
O18 - Protocol: skype4com - {FFC8B962-9B40-4DFF-9458-1830C7DD7F5D} - C:
\PROGRA~1\FILECO~1\Skype\SKYPE4~1.DLL
O20 - Winlogon Notify: dimsntfy - %SystemRoot%\System32\dimsntfy.dll (file
missing)
O23 - Service: avast! Antivirus - AVAST Software - C:\Programmi\Alwil
Software\Avast5\AvastSvc.exe
O23 - Service: avast! Mail Scanner - AVAST Software - C:\Programmi\Alwil
Software\Avast5\AvastSvc.exe
O23 - Service: avast! Web Scanner - AVAST Software - C:\Programmi\Alwil
Software\Avast5\AvastSvc.exe
O23 - Service: Servizio di Google Update (gupdate1c9bc72530e27a0)
(gupdate1c9bc72530e27a0) - Unknown owner - C:
\Programmi\Google\Update\GoogleUpdate.exe" /svc (file missing)
O23 - Service: Google Software Updater (gusvc) - Google - C:
\Programmi\Google\Common\Google Updater\GoogleUpdaterService.exe
O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision
Corporation - C:\Programmi\File comuni\InstallShield\Driver\1150\Intel
32\IDriverT.exe
O23 - Service: NBService - Nero AG - C:\Programmi\Nero\Nero 7\Nero
BackItUp\NBService.exe
O23 - Service: NMIndexingService - Nero AG - C:\Programmi\File
comuni\Ahead\Lib\NMIndexingService.exe

Ciao.
Forse è meglio se fai la scansione con HJT aggiornato.
http://www.aiutamici.com/software?ID=11175
Disistalla prima la versione vecchia.

Scarica ed installa MalwareBytes:
clicca qui per il download : http://www.aiutamici.com/software?id=80346
Prima di fare la scansione AGGIORNALO. (è molto importante)
Esegui una scansione completa del sistema.
Posta il log.
E anche un log di HJT (Aggiornato)