system
2
Hi,
what happens if you boot to SafeMode (F8-Boot)
Please read “VirusRemoval” below and if possible, post a log of Hijackthis
It seems like the entry
shell=explorer.exe
in your system.ini was damaged
actually this is only mirrored/mapped somehow into system.ini by e.g these registry entries:
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon]
“Shell”=“Explorer.exe”
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\IniFileMapping\system.ini\boot]
“Shell”=“SYS:Microsoft\Windows NT\CurrentVersion\Winlogon”
do you have those entries still ?

a repair of win with the XP-Setup-CD,
or recovering/going back to an earlier RESTORE-point might also be an option…