Dell said human error was to blame for mistakes which led it to ship a number of replacement server motherboards to customers pre-loaded with spyware.
The company declined to say whether it was running anti-virus software at its factory but said it had taken 16 steps to improve processes.
The infection hit replacement PowerEdge 310, 410, 510 and T410 boards. The direct seller said less than one per cent of boards were affected and complete new server systems were quite safe.
Dell is still not admitting how the W32.Spybot worm got into its systems and onto its hardware.
A Dell spokesman said the problem was worldwide but all infected motherboards had now been removed from the supply chain and it was already shipping clean boards.
He said the spyware would only infect people running unpatched versions of Windows without any anti-virus software - so that's presumably what Dell factories run on.
Daisy Nguyen, IT director for the Computer Science Department at Columbia University has asked Dell, via its forum, for a loan of an example of the infected hardware for research purposes. She runs almost 100 R410 servers at the university. She has yet to receive a reply from the company. ®