A virus in the production systems of computer giant Dell's Limerick plant is understood to have cost the company millions of pounds.
Work at the complex, which employs 3,400 people, was suspended for at least two working days and 12,000 computer units were recalled for checking.
The so-called FunLove virus was identified in Dell's production process last Thursday afternoon. It was discovered in systems used to install software in newly-built computers.
Production was shut down immediately and 12,000 units, which the company calculated may have been affected, were recalled. Dell builds computers to order and delivers them automatically on completion.
According to a spokeswoman for Dell, only 500 units had reached their final destination and each of the customers involved was contacted by the company. These units - and the remaining 11,500 computers in transit - were checked over the weekend and all were found to be free of the virus. Normal production resumed on Monday afternoon.
"When the virus was detected first, we had to take immediate precautions to ensure the shipped units were not contaminated," the spokeswoman said.
Dell refused to put a figure on the cost of the disruption but one industry source estimated that it may have cost as much as £14 million. The spokeswoman said production was not scheduled over the weekend because the company had just completed its latest quarter involving around-the-clock operations.
Dell now plans to make up the lost production hours through overtime and weekend work. According to the company, orders placed for desktop computers since Monday will be delayed by two days, while the estimated wait for other products is expected to be slightly longer.
The FunLove virus infects both desktop computers and computer servers running Windows 95, 98 and Windows NT operating systems. As it spreads it increases the size of the files it infects by placing a copy of itself at the end of the infected file. When the file is opened under the basic operating system DOS, it launches the message "Fun Loving Criminal".
Anti-virus companies said last week that FunLove would be easy to control as long as standard anti-virus procedures were implemented. Dell says it installed a "fix" early on Thursday and the virus was detected in internal systems that afternoon.
A number of Irish companies took measures last week to protect their computer systems against the same virus. They included Bank of Ireland, AIB, Ericsson, Microsoft, Eircom, the Revenue Commissioners and Smurfit.