Schonmal den Postausgang des Kontos überprüft? Vielleicht kann man anhand dessen ja etwas feststellen.
Am besten mal von 'nem 100%ig virenfreien Rechner überprüfen und mal das PW ändern

Werd ich gleich mal machen.

Hier der HijackThis Log vom zweiten PC:



Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 22:04:19, on 07.10.2009
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v6.00 SP2 (6.00.2900.2180)
Boot mode: Normal

Running processes:
C:\WINDOWS\System32\smss.exe
C:\WINDOWS\system32\csrss.exe
C:\WINDOWS\system32\winlogon.exe
C:\WINDOWS\system32\services.exe
C:\WINDOWS\system32\lsass.exe
C:\WINDOWS\system32\Ati2evxx.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\Ati2evxx.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\Explorer.EXE
C:\WINDOWS\system32\spoolsv.exe
C:\Programme\Avira\AntiVir Desktop\sched.exe
C:\Programme\Avira\AntiVir Desktop\avguard.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\SOUNDMAN.EXE
C:\Programme\avmwlanstick\wlangui.exe
C:\Programme\Microsoft IntelliPoint\ipoint.exe
C:\Programme\Microsoft IntelliType Pro\itype.exe
C:\Programme\CyberLink\PowerDVD8\PDVD8Serv.exe
C:\Programme\Avira\AntiVir Desktop\avgnt.exe
C:\Programme\Spyware Doctor\pctsTray.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Programme\Spybot - Search & Destroy\TeaTimer.exe
C:\Programme\avmwlanstick\WlanNetService.exe
C:\Programme\Bonjour\mDNSResponder.exe
C:\Programme\CyberLink\Shared files\RichVideo.exe
C:\Programme\Google\Update\GoogleUpdate.exe
C:\Programme\Spyware Doctor\pctsAuxs.exe
C:\Programme\Google\Update\1.2.183.7\GoogleCrashHandler.exe
C:\Programme\Spyware Doctor\pctsSvc.exe
C:\WINDOWS\System32\TUProgSt.exe
C:\WINDOWS\System32\alg.exe
C:\WINDOWS\system32\wbem\wmiprvse.exe
C:\Programme\Trend Micro\HijackThis\HijackThis.exe
C:\WINDOWS\system32\wbem\wmiprvse.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://www.google.de/
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyOverride = *.local
O2 - BHO: Spybot-S&D IE Protection - {53707962-6F74-2D53-2644-206D7942484F} - C:\PROGRA~1\SPYBOT~1\SDHelper.dll
O2 - BHO: Google Toolbar Notifier BHO - {AF69DE43-7D58-4638-B6FA-CE66B5AD205D} - C:\Programme\Google\GoogleToolbarNotifier\5.1.1309.3572\swg.dll
O4 - HKLM\..\Run: [SoundMan] SOUNDMAN.EXE
O4 - HKLM\..\Run: [AVMWlanClient] C:\Programme\avmwlanstick\wlangui.exe
O4 - HKLM\..\Run: [IntelliPoint] "c:\Programme\Microsoft IntelliPoint\ipoint.exe"
O4 - HKLM\..\Run: [itype] "c:\Programme\Microsoft IntelliType Pro\itype.exe"
O4 - HKLM\..\Run: [KernelFaultCheck] %systemroot%\system32\dumprep 0 -k
O4 - HKLM\..\Run: [RemoteControl8] C:\Programme\CyberLink\PowerDVD8\PDVD8Serv.exe
O4 - HKLM\..\Run: [PDVD8LanguageShortcut] C:\Programme\CyberLink\PowerDVD8\Language\Language.exe
O4 - HKLM\..\Run: [avgnt] "C:\Programme\Avira\AntiVir Desktop\avgnt.exe" /min
O4 - HKLM\..\Run: [ISTray] "C:\Programme\Spyware Doctor\pctsTray.exe"
O4 - HKCU\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\ctfmon.exe
O4 - HKCU\..\Run: [SpybotSD TeaTimer] C:\Programme\Spybot - Search & Destroy\TeaTimer.exe
O4 - HKUS\S-1-5-19\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\CTFMON.EXE (User 'LOKALER DIENST')
O4 - HKUS\S-1-5-20\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\CTFMON.EXE (User 'NETZWERKDIENST')
O4 - HKUS\S-1-5-18\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\CTFMON.EXE (User 'SYSTEM')
O4 - HKUS\.DEFAULT\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\CTFMON.EXE (User 'Default user')
O8 - Extra context menu item: Nach Microsoft &Excel exportieren - res://C:\PROGRA~1\MICROS~2\Office10\EXCEL.EXE/3000
O9 - Extra button: (no name) - {DFB852A3-47F8-48C4-A200-58CAB36FD2A2} - C:\PROGRA~1\SPYBOT~1\SDHelper.dll
O9 - Extra 'Tools' menuitem: Spybot - Search & Destroy Configuration - {DFB852A3-47F8-48C4-A200-58CAB36FD2A2} - C:\PROGRA~1\SPYBOT~1\SDHelper.dll
O9 - Extra button: ICQ6 - {E59EB121-F339-4851-A3BA-FE49C35617C2} - C:\Programme\ICQ6.5\ICQ.exe
O9 - Extra 'Tools' menuitem: ICQ6 - {E59EB121-F339-4851-A3BA-FE49C35617C2} - C:\Programme\ICQ6.5\ICQ.exe
O17 - HKLM\System\CCS\Services\Tcpip\..\{27D2039F-EB23-451C-8325-4173D1F50E6E}: NameServer = 208.67.220.220,208.67.222.222
O17 - HKLM\System\CCS\Services\Tcpip\..\{C6A2333D-029C-4830-8201-0D4C33556F6A}: NameServer = 208.67.220.220,208.67.222.222
O17 - HKLM\System\CS1\Services\Tcpip\Parameters: NameServer = 208.67.220.220,208.67.222.222
O17 - HKLM\System\CS1\Services\Tcpip\..\{27D2039F-EB23-451C-8325-4173D1F50E6E}: NameServer = 208.67.220.220,208.67.222.222
O17 - HKLM\System\CS2\Services\Tcpip\Parameters: NameServer = 208.67.220.220,208.67.222.222
O17 - HKLM\System\CS2\Services\Tcpip\..\{27D2039F-EB23-451C-8325-4173D1F50E6E}: NameServer = 208.67.220.220,208.67.222.222
O17 - HKLM\System\CCS\Services\Tcpip\Parameters: NameServer = 208.67.220.220,208.67.222.222
O23 - Service: Avira AntiVir Planer (AntiVirSchedulerService) - Avira GmbH - C:\Programme\Avira\AntiVir Desktop\sched.exe
O23 - Service: Avira AntiVir Guard (AntiVirService) - Avira GmbH - C:\Programme\Avira\AntiVir Desktop\avguard.exe
O23 - Service: Ati HotKey Poller - ATI Technologies Inc. - C:\WINDOWS\system32\Ati2evxx.exe
O23 - Service: ATI Smart - Unknown owner - C:\WINDOWS\system32\ati2sgag.exe
O23 - Service: AVM WLAN Connection Service - AVM Berlin - C:\Programme\avmwlanstick\WlanNetService.exe
O23 - Service: Bonjour-Dienst (Bonjour Service) - Apple Inc. - C:\Programme\Bonjour\mDNSResponder.exe
O23 - Service: Google Update Service (gupdate1c98d0661552ee4) (gupdate1c98d0661552ee4) - Google Inc. - C:\Programme\Google\Update\GoogleUpdate.exe
O23 - Service: iPod Service - Apple Inc. - C:\Programme\iPod\bin\iPodService.exe
O23 - Service: Cyberlink RichVideo Service(CRVS) (RichVideo) - Unknown owner - C:\Programme\CyberLink\Shared files\RichVideo.exe
O23 - Service: PC Tools Auxiliary Service (sdAuxService) - PC Tools - C:\Programme\Spyware Doctor\pctsAuxs.exe
O23 - Service: PC Tools Security Service (sdCoreService) - PC Tools - C:\Programme\Spyware Doctor\pctsSvc.exe
O23 - Service: TuneUp Drive Defrag-Dienst (TuneUp.Defrag) - TuneUp Software - C:\WINDOWS\System32\TuneUpDefragService.exe
O23 - Service: TuneUp Program Statistics Service (TuneUp.ProgramStatisticsSvc) - TuneUp Software - C:\WINDOWS\System32\TUProgSt.exe

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End of file - 6192 bytes