Trojan keeps coming back. Can't find source.

From: Michael Lester (mhl@attbi.com)
Date: 03/29/03 

From: Michael Lester <mhl@attbi.com>
Date: Sat, 29 Mar 2003 15:55:55 GMT

Hi,

I have spent days trying to rid my Win2000 system of trojans, but they
keep coming back. I think I finally got rid of deloder, but I can't
get rid of Backdoor IRC Cloner. Every time I delete
ocxdll.exe/dll32nt.hlp, it comes back. I can't find any other files on
my computer that is supposedly generates, and I find no entry in my
registry that looks suspicious.

My security was nil, because I thought my NetGear RT314 Router with
Firewall was protecting me. But even after I installed and ZoneAlarm
and reset my User names and passwords to something hard to guess, the
file keeps returning. And now I can't login to what was once my guest
account. When I reboot it hangs on the login screen for about a
minute.

Will someone help me get rid of this trojan and close the hole it's
coming in?

Thanks, Michael