Viruses, possible hacker?

Dont know whats been downloaded onto this computer, but theres gotta be viruses on here. In msconfig I saw something suspicious called japypun.exe, disabled that. Also when trying to open certain programs I get an error saying something like, "There is no disk in the drive. Please insert a disk into drive \device\harddisk5\dr8." Never seen this before. Also when I try to do things that involve registry editing, I get an error message saying "Registry editing has been disabled by your administrator" I am the administrator and there are no other users, also I cant get into Safe Mode. Heres a hijackthis log:

Logfile of HijackThis v1.99.1
Scan saved at 16:31:19, on 18/04/2009
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v6.00 SP2 (6.00.2900.2180)

Running processes:
C:\Program Files\Common Files\Apple\Mobile Device Support\bin\AppleMobileDeviceService.exe
C:\Program Files\Bonjour\mDNSResponder.exe
C:\Documents and Settings\doobie\Local Settings\Application Data\Google\Update\GoogleUpdateBeta.exe
C:\Program Files\Java\jre6\bin\jqs.exe
C:\Program Files\Nero\Nero8\Nero BackItUp\NBService.exe
C:\Program Files\Java\jre6\bin\jusched.exe
C:\Program Files\Zone Labs\ZoneAlarm\zlclient.exe
C:\Program Files\Norton Internet Security\Engine\\ccSvcHst.exe
C:\Program Files\Norton Internet Security\Engine\\ccSvcHst.exe
C:\Program Files\MSN Messenger\usnsvc.exe
C:\Program Files\MSN Messenger\msnmsgr.exe
C:\Program Files\Mozilla Firefox\firefox.exe
C:\Program Files\HijackThis\HijackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page =
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyOverride = *.local
O3 - Toolbar: Norton Toolbar - {7FEBEFE3-6B19-4349-98D2-FFB09D4B49CA} - C:\Program Files\Norton Internet Security\Engine\\coIEPlg.dll
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Program Files\Java\jre6\bin\jusched.exe"
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\system32\NvCpl.dll,NvStartup
O4 - HKLM\..\Run: [NeroFilterCheck] C:\Program Files\Common Files\Nero\Lib\NeroCheck.exe
O4 - HKLM\..\Run: [ZoneAlarm Client] "C:\Program Files\Zone Labs\ZoneAlarm\zlclient.exe"
O4 - HKCU\..\Run: [msnmsgr] "C:\Program Files\MSN Messenger\msnmsgr.exe" /background
O7 - HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System, DisableRegedit=1
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
O10 - Unknown file in Winsock LSP: c:\program files\bonjour\mdnsnsp.dll
O16 - DPF: {1E54D648-B804-468d-BC78-4AFFED8E262E} (System Requirements Lab) -
O18 - Protocol: livecall - {828030A1-22C1-4009-854F-8E305202313F} - C:\PROGRA~1\MSNMES~1\MSGRAP~1.DLL
O18 - Protocol: msnim - {828030A1-22C1-4009-854F-8E305202313F} - C:\PROGRA~1\MSNMES~1\MSGRAP~1.DLL
O20 - AppInit_DLLs: c:\progra~1\ThunMail\testabd.dll
O20 - Winlogon Notify: nnnkIyWm - nnnkIyWm.dll (file missing)
O23 - Service: Apple Mobile Device - Apple Inc. - C:\Program Files\Common Files\Apple\Mobile Device Support\bin\AppleMobileDeviceService.exe
O23 - Service: Bonjour Service - Apple Inc. - C:\Program Files\Bonjour\mDNSResponder.exe
O23 - Service: Google Update Service (GoogleUpdateBeta) - Google Corporation - C:\Documents and Settings\doobie\Local Settings\Application Data\Google\Update\GoogleUpdateBeta.exe
O23 - Service: iPod Service - Apple Inc. - C:\Program Files\iPod\bin\iPodService.exe
O23 - Service: Java Quick Starter (JavaQuickStarterService) - Unknown owner - C:\Program Files\Java\jre6\bin\jqs.exe" -service -config "C:\Program Files\Java\jre6\lib\deploy\jqs\jqs.conf (file missing)
O23 - Service: Nero BackItUp Scheduler 3 - Nero AG - C:\Program Files\Nero\Nero8\Nero BackItUp\NBService.exe
O23 - Service: Norton Internet Security - Unknown owner - C:\Program Files\Norton Internet Security\Engine\\ccSvcHst.exe" /s "Norton Internet Security" /m "C:\Program Files\Norton Internet Security\Engine\\diMaster.dll" /prefetch:1 (file missing)
O23 - Service: nProtect GameGuard Service (npggsvc) - Unknown owner - C:\WINDOWS\system32\GameMon.des.exe (file missing)
O23 - Service: NVIDIA Display Driver Service (NVSvc) - NVIDIA Corporation - C:\WINDOWS\system32\nvsvc32.exe
O23 - Service: PLFlash DeviceIoControl Service - Prolific Technology Inc. - C:\WINDOWS\system32\IoctlSvc.exe
O23 - Service: TrueVector Internet Monitor (vsmon) - Check Point Software Technologies LTD - C:\WINDOWS\system32\ZoneLabs\vsmon.exe

Thanks everyone

Atomic Rooster

Omnipotent One
You might want to have a look at these entries:

R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Int ernet Settings,ProxyOverride = *.local

O7 - HKCU\Software\Microsoft\Windows\CurrentVersion\Pol icies\System, DisableRegedit=1

O16 - DPF: {1E54D648-B804-468d-BC78-4AFFED8E262E} (System Requirements Lab) -

O20 - AppInit_DLLs: c:\progra~1\ThunMail\testabd.dll

O20 - Winlogon Notify: nnnkIyWm - nnnkIyWm.dll (file missing)

A really good program to use to clear up any viruses or malware is Malwarebytes' Anti-Malware. It's free to use and does a great job at catching the nasties.

Another good program to clean up your registry and other parts of your system would be CCleaner.