I am the administrator on my computer, yet my computer won't allow me to change my computer login password. There are certain programs that I can't delete via "Add or Remove Programs". I tried to remove my anti-virus (Avast Anti-Virus), and it would not do anything. I tried to install Ad-Aware 2007 and in the middle of installation it said,
"Error 1920. Service 'Ad-Aware 2007 Service' (aawservice) failed to start. Verify that you have sufficient privileges to start system services."
I get the feeling that someone has taken control of my computer. Please help me!

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:\Program Files\Windows Defender\MsMpEng.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\ZoneLabs\vsmon.exe
C:\WINDOWS\System32\wltrysvc.exe
C:\WINDOWS\System32\bcmwltry.exe
C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
C:\Program Files\Alwil Software\Avast4\ashServ.exe
C:\WINDOWS\system32\spoolsv.exe
C:\Program Files\Common Files\Microsoft Shared\VS7DEBUG\MDM.EXE
C:\Program Files\Microsoft SQL Server\MSSQL\Binn\sqlservr.exe
C:\Program Files\Dell\NICCONFIGSVC\NICCONFIGSVC.exe
C:\Program Files\Microsoft SQL Server\MSSQL\Binn\sqlagent.EXE
C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe
C:\Program Files\Alwil Software\Avast4\ashWebSv.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\Explorer.EXE
C:\Program Files\Synaptics\SynTP\SynTPEnh.exe
C:\WINDOWS\system32\hkcmd.exe
C:\WINDOWS\system32\igfxpers.exe
C:\Program Files\Java\jre1.6.0_01\bin\jusched.exe
C:\WINDOWS\stsystra.exe
C:\WINDOWS\system32\igfxsrvc.exe
C:\WINDOWS\system32\WLTRAY.exe
C:\Program Files\Common Files\InstallShield\UpdateService\issch.exe
C:\Program Files\HP\hpcoretech\hpcmpmgr.exe
C:\Program Files\Scansoft\PaperPort\pptd40nt.exe
C:\Program Files\Zone Labs\ZoneAlarm\zlclient.exe
C:\Program Files\Alt-Tab Thingy v3\attmain.exe
C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
C:\Program Files\Windows Defender\MSASCui.exe
C:\Program Files\iTunes\iTunesHelper.exe
C:\Program Files\iPod\bin\iPodService.exe
C:\Program Files\YourWare Solutions\FreeRAM XP Pro\FreeRAM XP Pro.exe
C:\Program Files\Digital Line Detect\DLG.exe
C:\Program Files\Microsoft SQL Server\80\Tools\Binn\sqlmangr.exe
C:\WINDOWS\BricoPacks\Vista Inspirat 2\RocketDock\RocketDock.exe
C:\WINDOWS\BricoPacks\Vista Inspirat 2\UberIcon\UberIcon Manager.exe
C:\WINDOWS\BricoPacks\Vista Inspirat 2\YzShadow\YzShadow.exe
C:\PROGRA~1\Yahoo!\MESSEN~1\ymsgr_tray.exe
C:\Documents and Settings\duncan\Desktop\HijackThis.exe
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://www.dell.com
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = http://www.dell.com
O2 - BHO: (no name) - {53707962-6F74-2D53-2644-206D7942484F} - C:\PROGRA~1\SPYBOT~1\SDHelper.dll
O2 - BHO: SSVHelper Class - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Program Files\Java\jre1.6.0_01\bin\ssv.dll
O4 - HKLM\..\Run: [SynTPEnh] C:\Program Files\Synaptics\SynTP\SynTPEnh.exe
O4 - HKLM\..\Run: [igfxtray] C:\WINDOWS\system32\igfxtray.exe
O4 - HKLM\..\Run: [igfxhkcmd] C:\WINDOWS\system32\hkcmd.exe
O4 - HKLM\..\Run: [igfxpers] C:\WINDOWS\system32\igfxpers.exe
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Program Files\Java\jre1.6.0_01\bin\jusched.exe"
O4 - HKLM\..\Run: [SigmatelSysTrayApp] stsystra.exe
O4 - HKLM\..\Run: [Dell Wireless Manager UI] C:\WINDOWS\system32\WLTRAY
O4 - HKLM\..\Run: [ISUSPM Startup] "C:\Program Files\Common Files\InstallShield\UpdateService\isuspm.exe" -startup
O4 - HKLM\..\Run: [ISUSScheduler] "C:\Program Files\Common Files\InstallShield\UpdateService\issch.exe" -start
O4 - HKLM\..\Run: [HP Component Manager] "C:\Program Files\HP\hpcoretech\hpcmpmgr.exe"
O4 - HKLM\..\Run: [HPDJ Taskbar Utility] C:\WINDOWS\system32\spool\drivers\w32x86\3\hpztsb07.exe
O4 - HKLM\..\Run: [PaperPort PTD] C:\Program Files\Scansoft\PaperPort\pptd40nt.exe
O4 - HKLM\..\Run: [IndexSearch] C:\Program Files\Scansoft\PaperPort\IndexSearch.exe
O4 - HKLM\..\Run: [MSKDetectorExe] C:\Program Files\McAfee\SpamKiller\MSKDetct.exe /uninstall
O4 - HKLM\..\Run: [ZoneAlarm Client] "C:\Program Files\Zone Labs\ZoneAlarm\zlclient.exe"
O4 - HKLM\..\Run: [Alt-Tab Thingy] "C:\Program Files\Alt-Tab Thingy v3\attmain.exe"
O4 - HKLM\..\Run: [BootSkin Startup Jobs] "C:\PROGRA~1\Stardock\WINCUS~1\BootSkin\BootSkin.exe" /StartupJobs
O4 - HKLM\..\Run: [avast!] C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
O4 - HKLM\..\Run: [Windows Defender] "C:\Program Files\Windows Defender\MSASCui.exe" -hide
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\qttask.exe" -atboottime
O4 - HKLM\..\Run: [iTunesHelper] "C:\Program Files\iTunes\iTunesHelper.exe"
O4 - HKCU\..\Run: [MSMSGS] "C:\Program Files\Messenger\msmsgs.exe" /background
O4 - HKCU\..\Run: [Yahoo! Pager] "C:\PROGRA~1\Yahoo!\MESSEN~1\YAHOOM~1.EXE" -quiet
O4 - HKCU\..\Run: [FreeRAM XP] "C:\Program Files\YourWare Solutions\FreeRAM XP Pro\FreeRAM XP Pro.exe" -win
O4 - HKCU\..\Run: [Alt-Tab Thingy] "C:\Program Files\Alt-Tab Thingy v3\attmain.exe"
O4 - Startup: RocketDock.lnk = C:\WINDOWS\BricoPacks\Vista Inspirat 2\RocketDock\RocketDock.exe
O4 - Startup: TransBar.lnk = C:\WINDOWS\BricoPacks\Vista Inspirat 2\TransBar\TransBar.exe
O4 - Startup: UberIcon.lnk = C:\WINDOWS\BricoPacks\Vista Inspirat 2\UberIcon\UberIcon Manager.exe
O4 - Startup: Y'z Shadow.lnk = C:\WINDOWS\BricoPacks\Vista Inspirat 2\YzShadow\YzShadow.exe
O4 - Global Startup: Adobe Reader Speed Launch.lnk = C:\Program Files\Adobe\Acrobat 7.0\Reader\reader_sl.exe
O4 - Global Startup: Digital Line Detect.lnk = ?
O4 - Global Startup: Service Manager.lnk = C:\Program Files\Microsoft SQL Server\80\Tools\Binn\sqlmangr.exe
O8 - Extra context menu item: E&xport to Microsoft Excel - res://C:\PROGRA~1\MICROS~2\OFFICE11\EXCEL.EXE/3000
O8 - Extra context menu item: Similar Pages - res://C:\Program Files\Google\GoogleToolbar1.dll/cmsimilar.html
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.6.0_01\bin\ssv.dll
O9 - Extra 'Tools' menuitem: Sun Java Console - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.6.0_01\bin\ssv.dll
O9 - Extra button: Research - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~2\OFFICE11\REFIEBAR.DLL
O9 - Extra button: (no name) - {CD67F990-D8E9-11d2-98FE-00C0F0318AFE} - (no file)
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)
O20 - Winlogon Notify: igfxcui - C:\WINDOWS\SYSTEM32\igfxdev.dll
O20 - Winlogon Notify: WgaLogon - C:\WINDOWS\SYSTEM32\WgaLogon.dll
O21 - SSODL: WPDShServiceObj - {AAA288BA-9A4C-45B0-95D7-94D524869DB5} - C:\WINDOWS\system32\WPDShServiceObj.dll
O23 - Service: avast! iAVS4 Control Service (aswUpdSv) - ALWIL Software - C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
O23 - Service: avast! Antivirus - ALWIL Software - C:\Program Files\Alwil Software\Avast4\ashServ.exe
O23 - Service: avast! Mail Scanner - Unknown owner - C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe" /service (file missing)
O23 - Service: avast! Web Scanner - Unknown owner - C:\Program Files\Alwil Software\Avast4\ashWebSv.exe" /service (file missing)
O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files\Common Files\InstallShield\Driver\1150\Intel 32\IDriverT.exe
O23 - Service: iPod Service - Apple Inc. - C:\Program Files\iPod\bin\iPodService.exe
O23 - Service: NICCONFIGSVC - Dell Inc. - C:\Program Files\Dell\NICCONFIGSVC\NICCONFIGSVC.exe
O23 - Service: Pml Driver HPZ12 - HP - C:\WINDOWS\system32\HPZipm12.exe
O23 - Service: TrueVector Internet Monitor (vsmon) - Zone Labs, LLC - C:\WINDOWS\system32\ZoneLabs\vsmon.exe
O23 - Service: WhosOn Scheduled Reports (WhosOnReports) - Unknown owner - C:\Program Files\WhosOnV4\WOScheduledReports.exe (file missing)
O23 - Service: Dell Wireless WLAN Tray Service (wltrysvc) - Unknown owner - C:\WINDOWS\System32\wltrysvc.exe