Can somebody tell me where i can find dllhost.exe for windows 2000 professional (english)?

I need it because i delete it before a worm (W32.welchi.worm) infected my hole system.
But now i don't know where i can find a new one.

Please somebody tell me where i can find a new one!!

Thank you.

dllhost.exe is included in the servicepacks of w2k.
the newest one is w2ksp4_en.exe.