Hola otra vez,
he hecho todo lo que me has puesto, pero el fichero C:\windows\sysbh.dll no estaba y no lo he borrado. Y luego no me deja actualizar windows con el service pack 2 (hace ya tiempo que me pasa), me dice que igual la clave de usuario de mi windows no es correcta. Lo del sspmydoom me parece que se ha quitado, te dejo el log por si acaso (aunque el programa zonealarm me manda alerta todavia). Muchas gracias!!!!

Logfile of HijackThis v1.99.0
Scan saved at 21:31:54, on 16/02/2005
Platform: Windows XP (WinNT 5.01.2600)
MSIE: Internet Explorer v6.00 (6.00.2600.0000)

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:\Program Files\Norton AntiVirus\navapsvc.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\Explorer.EXE
C:\WINDOWS\system32\ZONELABS\vsmon.exe
C:\Program Files\Zone Labs\ZoneAlarm\zlclient.exe
C:\Program Files\QuickTime\qttask.exe
C:\Program Files\Hewlett-Packard\Digital Imaging\Unload\hpqcmon.exe
C:\Program Files\Hewlett-Packard\HP Share-to-Web\hpgs2wnd.exe
C:\PROGRA~1\NORTON~1\navapw32.exe
C:\PROGRA~1\TERRAA~1\BIN\WIN2K\tidslmon.exe
C:\Program Files\Hewlett-Packard\HP Share-to-Web\hpgs2wnf.exe
C:\WINDOWS\System32\wuauclt.exe
C:\HJ\HijackThis.exe

O3 - Toolbar: Norton AntiVirus - {42CDD1BF-3FFB-4238-8AD1-7859DF00B1D6} - C:\Program Files\Norton AntiVirus\NavShExt.dll
O4 - HKLM\..\Run: [Zone Labs Client] "C:\Program Files\Zone Labs\ZoneAlarm\zlclient.exe"
O4 - HKLM\..\Run: [SSC_UserPrompt] C:\Program Files\Common Files\Symantec Shared\Security Center\UsrPrmpt.exe
O4 - HKLM\..\Run: [Symantec NetDriver Monitor] C:\PROGRA~1\SYMNET~1\SNDMon.exe
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\qttask.exe" -atboottime
O4 - HKLM\..\Run: [CamMonitor] C:\Program Files\Hewlett-Packard\Digital Imaging\Unload\hpqcmon.exe
O4 - HKLM\..\Run: [Share-to-Web Namespace Daemon] C:\Program Files\Hewlett-Packard\HP Share-to-Web\hpgs2wnd.exe
O4 - HKLM\..\Run: [NAV Agent] C:\PROGRA~1\NORTON~1\navapw32.exe
O4 - HKLM\..\Run: [NeroFilterCheck] C:\WINDOWS\system32\NeroCheck.exe
O4 - HKLM\..\Run: [TIxDSL] C:\PROGRA~1\TERRAA~1\BIN\WIN2K\tidslmon.exe
O4 - HKCU\..\Run: [NBJ] "C:\Program Files\Ahead\Nero BackItUp\NBJ.exe"
O8 - Extra context menu item: E&xporter vers Microsoft Excel - res://C:\PROGRA~1\MICROS~2\OFFICE11\EXCEL.EXE/3000
O9 - Extra button: Recherche - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~2\OFFICE11\REFIEBAR.DLL
O16 - DPF: {4F1E5B1A-2A80-42CA-8532-2D05CB959537} (MSN Photo Upload Tool) - http://by103fd.bay103.hotmail.msn.co...s/MsnPUpld.cab
O16 - DPF: {6414512B-B978-451D-A0D8-FCFDF33E833C} (WUWebControl Class) - http://v5.windowsupdate.microsoft.co...?1100183590873
O16 - DPF: {9A9307A0-7DA4-4DAF-B042-5009F29E09E1} (ActiveScan Installer Class) - http://www.pandasoftware.com/activescan/as5/asinst.cab
O17 - HKLM\System\CCS\Services\Tcpip\..\{E2E51648-9E01-475B-ADDD-EFD6CB305741}: NameServer = 195.235.113.3,195.235.96.90
O23 - Service: Norton AntiVirus Auto Protect Service - Symantec Corporation - C:\Program Files\Norton AntiVirus\navapsvc.exe
O23 - Service: ScriptBlocking Service - Symantec Corporation - C:\PROGRA~1\COMMON~1\SYMANT~1\SCRIPT~1\SBServ.exe
O23 - Service: Symantec Network Drivers Service - Symantec Corporation - C:\Program Files\Common Files\Symantec Shared\SNDSrvc.exe
O23 - Service: SymWMI Service - Symantec Corporation - C:\Program Files\Common Files\Symantec Shared\Security Center\SymWSC.exe
O23 - Service: TrueVector Internet Monitor - Zone Labs Inc. - C:\WINDOWS\system32\ZONELABS\vsmon.exe