I know I have 2 PCs on the LAN that are infected with unknown viruses sending spam on port 25. PC1 is opening instances of iexplore.exe that is connecting to a russian server, probably getting data and then spamming. I haven't traced the exe that is spawining this but I think it can.
PC2 is a bigger problem. I see from my router's logs that it is spamming but using x-netstat I don't see a process running that's connecting on port 25. It must be hidden. I've used rootkit revealer and McAfee's rootkit detective, spybot, adaware and hijackthis. I've looked for unusual services also and nothing has been found at all. I must have a hidden process or rootkit running.
How do I find the source? Any other tricks or tips?