whatever that is... i think i have that problem, but am out of my depth with it.
have scanned with updated Avira (free version) and SUPERAntiSpyware (paid version). neither found anything...
have manually removed all cookies, including suspicious looking yandex.ru and told firefox not to accept any more cookies.
when clicking "home" browser redirects to Thomson Speedtouch page at seemingly random moments and shows a line beginning with dsldevice.lan/cgi/b/ic/connect/?nm=1&client=
in address bar.
would appreciate your advice.

hijackthis log:

Logfile of Trend Micro HijackThis v2.0.3 (BETA)
Scan saved at 22:31:27, on 2-1-2010
Platform: Windows XP SP3 (WinNT 5.01.2600)
MSIE: Internet Explorer v8.00 (8.00.6001.18702)
Boot mode: Normal

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\Avira\AntiVir Desktop\sched.exe
C:\WINDOWS\Explorer.EXE
C:\Program Files\Thomson SpeedTouch\SpeedTouch 120g Wireless USB Monitor\PRISMSVR.EXE
C:\WINDOWS\system32\RUNDLL32.EXE
C:\Program Files\Avira\AntiVir Desktop\avgnt.exe
C:\Program Files\Creative\SBLive\Diagnostics\diagent.exe
C:\Program Files\Unlocker\UnlockerAssistant.exe
C:\Program Files\Java\jre6\bin\jusched.exe
C:\Program Files\SUPERAntiSpyware\SUPERAntiSpyware.exe
C:\Program Files\xNeat Clipboard Manager\xNeatClipMngr.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Program Files\Thomson SpeedTouch\SpeedTouch 120g Wireless USB Monitor\st120g.exe
C:\Program Files\Common Files\ArcSoft\Connection Service\Bin\ACService.exe
C:\Program Files\Avira\AntiVir Desktop\avguard.exe
C:\WINDOWS\system32\CTsvcCDA.exe
C:\Program Files\Java\jre6\bin\jqs.exe
C:\Program Files\Common Files\Microsoft Shared\VS7DEBUG\MDM.EXE
C:\WINDOWS\system32\nvsvc32.exe
C:\WINDOWS\system32\HPZipm12.exe
C:\WINDOWS\System32\svchost.exe
C:\Program Files\UPHClean\uphclean.exe
C:\WINDOWS\system32\MsPMSPSv.exe
C:\Program Files\Mozilla Firefox\firefox.exe
C:\WINDOWS\System32\msiexec.exe
C:\Program Files\TrendMicro\HiJackThis\HiJackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = Google
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = Hotmail, News, Sport, Music, Movies, Money, Cars, Shopping, Windows Live from MSN UK
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = Bing
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = Bing
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = Hotmail, News, Sport, Music, Movies, Money, Cars, Shopping, Windows Live from MSN UK
O2 - BHO: AskBar BHO - {201f27d4-3704-41d6-89c1-aa35e39143ed} - C:\Program Files\AskBarDis\bar\bin\askBar.dll
O2 - BHO: Java(tm) Plug-In 2 SSV Helper - {DBC80044-A445-435b-BC74-9C25C1C588A9} - C:\Program Files\Java\jre6\bin\jp2ssv.dll
O2 - BHO: JQSIEStartDetectorImpl - {E7E6F031-17CE-4C07-BC86-EABFE594F69C} - C:\Program

Files\Java\jre6\lib\deploy\jqs\ie\jqs_plugin.dll
O3 - Toolbar: Foxit Toolbar - {3041d03e-fd4b-44e0-b742-2d9b88305f98} - C:\Program Files\AskBarDis\bar\bin\askBar.dll
O4 - HKLM\..\Run: [PRISMSVR.EXE] "C:\Program Files\Thomson SpeedTouch\SpeedTouch 120g Wireless USB Monitor\PRISMSVR.EXE"

/APPLY
O4 - HKLM\..\Run: [diagent] "C:\Program Files\Creative\SBLive\Diagnostics\diagent.exe" startup
O4 - HKLM\..\Run: [UpdReg] C:\WINDOWS\UpdReg.EXE
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\system32\NvCpl.dll,NvStartup
O4 - HKLM\..\Run: [nwiz] nwiz.exe /install
O4 - HKLM\..\Run: [NvMediaCenter] RUNDLL32.EXE C:\WINDOWS\system32\NvMcTray.dll,NvTaskbarInit
O4 - HKLM\..\Run: [avgnt] "C:\Program Files\Avira\AntiVir Desktop\avgnt.exe" /min
O4 - HKLM\..\Run: [UnlockerAssistant] "C:\Program Files\Unlocker\UnlockerAssistant.exe"
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Program Files\Java\jre6\bin\jusched.exe"
O4 - HKCU\..\Run: [ccleaner] "C:\Program Files\CCleaner\ccleaner.exe" /AUTO
O4 - HKCU\..\Run: [SUPERAntiSpyware] C:\Program Files\SUPERAntiSpyware\SUPERAntiSpyware.exe
O4 - HKCU\..\Run: [xNeat Clipboard Manager] C:\Program Files\xNeat Clipboard Manager\xNeatClipMngr.exe
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O4 - HKUS\S-1-5-18\..\Run: [DWQueuedReporting] "C:\PROGRA~1\COMMON~1\MICROS~1\DW\dwtrig20.exe " -t (User 'SYSTEM')
O4 - HKUS\.DEFAULT\..\Run: [DWQueuedReporting] "C:\PROGRA~1\COMMON~1\MICROS~1\DW\dwtrig20.exe " -t (User 'Default user')
O4 - Global Startup: SpeedTouch 120g Wireless USB Monitor.lnk = C:\Program Files\Thomson SpeedTouch\SpeedTouch 120g Wireless USB

Monitor\st120g.exe
O8 - Extra context menu item: E&xport to Microsoft Excel - res://C:\PROGRA~1\MICROS~2\OFFICE11\EXCEL.EXE/3000
O9 - Extra button: (no name) - {e2e2dd38-d088-4134-82b7-f2ba38496583} - C:\WINDOWS\Network Diagnostic\xpnetdiag.exe
O9 - Extra 'Tools' menuitem: @xpsp3res.dll,-20001 - {e2e2dd38-d088-4134-82b7-f2ba38496583} - C:\WINDOWS\Network

Diagnostic\xpnetdiag.exe
O9 - Extra button: Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe
O9 - Extra 'Tools' menuitem: Windows Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program

Files\Messenger\msmsgs.exe
O16 - DPF: {6414512B-B978-451D-A0D8-FCFDF33E833C} (WUWebControl Class) -

http://www.update.microsoft.com/wind...?1185202870578
O16 - DPF: {6E32070A-766D-4EE6-879C-DC1FA91D2FC3} (MUWebControl Class) -

http://www.update.microsoft.com/micr...?1186569480156
O17 - HKLM\System\CCS\Services\Tcpip\..\{21396A31-6270-4C2F-BD8B-B149B120EBF8}: NameServer = 192.168.1.254
O17 - HKLM\System\CS1\Services\Tcpip\..\{21396A31-6270-4C2F-BD8B-B149B120EBF8}: NameServer = 192.168.1.254
O17 - HKLM\System\CS2\Services\Tcpip\..\{21396A31-6270-4C2F-BD8B-B149B120EBF8}: NameServer = 192.168.1.254
O20 - Winlogon Notify: !SASWinLogon - C:\Program Files\SUPERAntiSpyware\SASWINLO.DLL
O22 - SharedTaskScheduler: Browseui preloader - {438755C2-A8BA-11D1-B96B-00A0C90312E1} - C:\WINDOWS\System32\browseui.dll
O22 - SharedTaskScheduler: Component Categories cache daemon - {8C7461EF-2B13-11d2-BE35-3078302C2030} -

C:\WINDOWS\System32\browseui.dll
O23 - Service: ArcSoft Connect Daemon (ACDaemon) - ArcSoft Inc. - C:\Program Files\Common Files\ArcSoft\Connection

Service\Bin\ACService.exe
O23 - Service: Avira AntiVir Scheduler (AntiVirSchedulerService) - Avira GmbH - C:\Program Files\Avira\AntiVir Desktop\sched.exe
O23 - Service: Avira AntiVir Guard (AntiVirService) - Avira GmbH - C:\Program Files\Avira\AntiVir Desktop\avguard.exe
O23 - Service: Symantec Lic NetConnect service (CLTNetCnService) - Unknown owner - C:\Program Files\Common Files\Symantec

Shared\ccSvcHst.exe (file missing)
O23 - Service: Creative Service for CDROM Access - Creative Technology Ltd - C:\WINDOWS\system32\CTsvcCDA.exe
O23 - Service: Wachtwoordvalidatie voor Symantec IS (ISPwdSvc) - Unknown owner - C:\Program Files\Norton Internet Security\isPwdSvc.exe

(file missing)
O23 - Service: Java Quick Starter (JavaQuickStarterService) - Sun Microsystems, Inc. - C:\Program Files\Java\jre6\bin\jqs.exe
O23 - Service: NVIDIA Display Driver Service (NVSvc) - NVIDIA Corporation - C:\WINDOWS\system32\nvsvc32.exe
O23 - Service: Pml Driver HPZ12 - HP - C:\WINDOWS\system32\HPZipm12.exe

--
End of file - 6958 bytes

Check this out:

Google

Did you go to "tools" > "internet options" > and try to change your home page to what you want?

this is not a matter of "losing" my homepage. instead of going back to my homepage my browser shows a message from Thomson Speedtouch that says my internet connection is gone. the only way to get my connection back is then to reset my modem/router and let windows fix the connenction. my homepage (google) turns up again fine.
are you saying PRISMSVR.exe is making my connection conk out?
and if so, can i remove this apparently obsolete program without further consequences?

are you useing that Thomson Speedtouch, is it your internet connection? Have you called your internet provider, you should and see what they say about it.