I'm not going to lie, I know exactly what caused this problem (because I just reformatted yesterday) and will not encounter it again. Hopefully, this will be a very easy fix.
I keep getting pop-ups when not on the internet, or browsing, etc. It's a problem I had months ago and was helped very quickly. I hope the same is true.
Logfile of HijackThis v1.99.1
Scan saved at 7:15:48 AM, on 6/7/2006
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v6.00 SP2 (6.00.2900.2180)
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:\Program Files\Intel\Wireless\Bin\EvtEng.exe
C:\Program Files\Intel\Wireless\Bin\WLKeeper.exe
C:\WINDOWS\system32\spoolsv.exe
C:\Program Files\Sophos\Remote Update\cachemgr.exe
C:\Program Files\Intel\Wireless\Bin\RegSrvc.exe
C:\Program Files\Sophos SWEEP for NT\SWEEPSRV.SYS
C:\WINDOWS\Explorer.EXE
C:\Program Files\ATI Technologies\ATI Control Panel\atiptaxx.exe
C:\WINDOWS\system32\dla\tfswctrl.exe
C:\Program Files\Intel\Wireless\Bin\ifrmewrk.exe
C:\Program Files\Java\jre1.5.0_03\bin\jusched.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Games\Steam\Steam.exe
C:\Program Files\Sophos SWEEP for NT\ICMON.EXE
C:\Program Files\Sophos\Remote Update\imonitor.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\ntvdm.exe
C:\Program Files\AIM\aim.exe
C:\WINDOWS\system32\dcomcfg.exe
C:\WINDOWS\system32\rundll32.exe
C:\WINDOWS\system32\atmclk.exe
C:\Program Files\SpywareQuake.com\spyware-quake.exe
C:\Program Files\SpywareQuake.com\spyware-quake.exe
C:\Program Files\Mozilla Firefox\firefox.exe
C:\Program Files\Hijack This\HijackThis.exe
O2 - BHO: AcroIEHlprObj Class - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Program Files\Adobe\Acrobat 7.0\ActiveX\AcroIEHelper.dll
O2 - BHO: DriveLetterAccess - {5CA3D70E-1895-11CF-8E15-001234567890} - C:\WINDOWS\system32\dla\tfswshx.dll
O2 - BHO: (no name) - {6ab7158b-4bff-4160-ad7d-4d622df548cf} - C:\WINDOWS\system32\hp100.tmp
O3 - Toolbar: SecurityToolbar - {736b5468-bdad-41be-92d0-22ae2ddf7bcb} - C:\Program Files\Security Toolbar\Security Toolbar.dll
O4 - HKLM\..\Run: [Apoint] C:\Program Files\Apoint\Apoint.exe
O4 - HKLM\..\Run: [ATIModeChange] Ati2mdxx.exe
O4 - HKLM\..\Run: [ATIPTA] C:\Program Files\ATI Technologies\ATI Control Panel\atiptaxx.exe
O4 - HKLM\..\Run: [Webroot Spy Sweeper, Enterprise Edition] C:\Program Files\Webroot\Enterprise\Spy Sweeper\SpySweeperTray.exe
O4 - HKLM\..\Run: [IgfxTray] C:\WINDOWS\system32\igfxtray.exe
O4 - HKLM\..\Run: [dla] C:\WINDOWS\system32\dla\tfswctrl.exe
O4 - HKLM\..\Run: [IntelWireless] C:\Program Files\Intel\Wireless\Bin\ifrmewrk.exe /tf Intel PROSet/Wireless
O4 - HKLM\..\Run: [SunJavaUpdateSched] C:\Program Files\Java\jre1.5.0_03\bin\jusched.exe
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O4 - HKCU\..\Run: [Steam] "C:\Games\Steam\Steam.exe" -silent
O4 - HKCU\..\RunOnce: [SantaCruzCpl] C:\Program Files\Turtle Beach\Santa Cruz\Control Panel\SantaCruzCpl.exe /restore
O4 - Global Startup: InterCheck Monitor.LNK = C:\Program Files\Sophos SWEEP for NT\ICMON.EXE
O4 - Global Startup: Remote Update Monitor.lnk = C:\Program Files\Sophos\Remote Update\imonitor.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) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\j2re1.4.1_04\bin\npjpi141_04.dll
O9 - Extra 'Tools' menuitem: Sun Java Console - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\j2re1.4.1_04\bin\npjpi141_04.dll
O9 - Extra button: Research - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~2\OFFICE11\REFIEBAR.DLL
O9 - Extra button: AIM - {AC9E2541-2814-11d5-BC6D-00B0D0A1DE45} - C:\Program Files\AIM\aim.exe
O16 - DPF: {01A88BB1-1174-41EC-ACCB-963509EAE56B} (SysProWmi Class) -
http://support.dell.com/systemprofiler/SysPro.CAB
O17 - HKLM\System\CCS\Services\Tcpip\..\{F0B5ACAA-2AAF-4EA1-B926-09B0EE176328}: NameServer = 71.243.0.12 68.237.161.12
O20 - Winlogon Notify: igfxcui - C:\WINDOWS\SYSTEM32\igfxsrvc.dll
O20 - Winlogon Notify: IntelWireless - C:\Program Files\Intel\Wireless\Bin\LgNotify.dll
O20 - Winlogon Notify: WgaLogon - C:\WINDOWS\SYSTEM32\WgaLogon.dll
O23 - Service: Ati HotKey Poller - Unknown owner - C:\WINDOWS\System32\Ati2evxx.exe
O23 - Service: Sophos Cache Manager (CacheMgr) - SOPHOS Plc - C:\Program Files\Sophos\Remote Update\cachemgr.exe
O23 - Service: EvtEng - Intel Corporation - C:\Program Files\Intel\Wireless\Bin\EvtEng.exe
O23 - Service: RegSrvc - Intel Corporation - C:\Program Files\Intel\Wireless\Bin\RegSrvc.exe
O23 - Service: Spectrum24 Event Monitor (S24EventMonitor) - Intel Corporation - C:\Program Files\Intel\Wireless\Bin\S24EvMon.exe
O23 - Service: Sophos Anti-Virus Network (SweepNet) - Sophos Plc - C:\Program Files\Sophos SWEEP for NT\SWNETSUP.EXE
O23 - Service: Sophos Anti-Virus (SWEEPSRV.SYS) - Sophos Plc - C:\Program Files\Sophos SWEEP for NT\SWEEPSRV.SYS
O23 - Service: WLANKEEPER - Intel® Corporation - C:\Program Files\Intel\Wireless\Bin\WLKeeper.exe