Network administrators were working to stop a fast-spreading e-mail worm that looks like a normal error message but actually contains a malicious program that spreads itself and installs a program that leaves an open door to infected computers. The worm — called “Mydoom,” “Novarg” or “WORM_MIMAIL.R” — was replicating itself so quickly that some corporate networks were clogged with infected traffic within hours of its appearance Monday. Its mail engine could send out 100 infected e-mail messages in 30 seconds, experts said. It runs on computers running Microsoft Corp.’s Windows operating systems, though other computers were affected by slow network and a flood of bogus messages. About 3,800 infections were confirmed within 45 minutes of its initial discovery, according to the security firm Central Command. Full Story