Unable to edit XP Registry

Please help me.

My XP system is under virus attack. Some unknown virus "DOWNLOAD.TROJAN" has caused this problem.

When I go through the XP Registry I see unknown entry next to this:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsNT\CurrentVersion\Winlogon

Shell —> Explorer.exe, C:\Windows\System32\iocce.exe
Userinit —> C:\WINDOWS\system32\userinit.exe, vjbac.exe

For some reason, I am not able to delete "C:\Windows\System32\iocce.exe" and "vjbac.exe" these entries from the registry.

- When I double click on this value, I can edit it and close. But when I open it again the deleted values comes back.

- I even tried to export the Winlogon registry tree and edited the text and re-imported it, even then the values are not getting deleted.

- I login as Administrator, and I set the permissions to Full. Even then I am not able to delete.

- Hijackthis is not able to fix this problem.

Please, can someone guide me.

Thanks.

Please go here:

HijackThis! Logs and Malware Removal

Start a new topic, and post your HijackThis! log file.