Visitors to dan.co.uk were offered a Pentium III 750Mhz laptop with a 15.1inch screen for precisely £0.00, plus £28.20 postage and packing.
The back-end software flaw first affected the site on Friday 23 February but the price was still available by late afternoon the following Monday.
Dan has so far refused to honour orders placed for the laptop during this period and says it is currently in discussions with customers who latched onto the extraordinary bargain.
Dan marketing manager Paul Tobin said the error occurred in the company's bespoke software during a pricing update.
"We've now put a number of procedures in place to ensure that this doesn't happen again. We've got a meeting scheduled this week with our legal side, directors and the person responsible for our Web site to discuss the matter and what to do," he added.
Computerweekly.com reader Ray Scott said that after placing his order for the laptop, he received two phone calls from a customer service representative claiming that the model he had ordered was out of stock and offering him a more expensive model at full price instead. He said he was aware of four other orders at the lower price.
Jon Fell, a partner at solicitors Mason, warned companies experiencing similar Web site problems that they could still be liable for the orders made. "In a test case in the 1970s involving car park ticket machines, it was found that a machine can create a contract on your behalf."
Fell said that errors of this kind had an impact on a company's reputation if it chose not to honour the deals made. In a similar case last year, PC vendor Dell honoured a series of extremely low prices for products that had been posted on its Web site by mistake.