problem with win xp startup file

Hello all

I hope you can help me with the following problem I am having with my system .

Upon selecting the user account i want to use the system comes up with an error message stating the windows is unable to find netdc.exe file in the windows-system32 folder .

This file was I believe was deleted by spysweeper or norton as a virus-trojan horse file.

Can anyone either , advise me of the following ;

a. the file was a genuine system file ,

b. the file was a trojan startup

c. email me with the file (so i can put it back in thesystem folder )

d. where to look in the registry so I can remove this seek at boot up from the system

I am running winXP pro on the system

I have looked for the file in the winxp cd disk i386 folder and can find no trace of it, which leads me to believe it may have been bogus

Also can anyone point me in the direction of a site that tells you what to look for in the process window of task manager to identify any trojans etc

Thanks for any help on this matter

Glenn