Intel now expects to post revenue of $13.4bn to $14bn (£8.6bn to £9bn) in the final quarter of 2011, down from the previous forecast of $14.7bn to $15.2bn.
Shares in the world's largest maker of microprocessors fell more than 4% after news of the reduced forecast.
Intel said that sales of PCs are expected to be "up sequentially" in the fourth quarter, but the worldwide supply chain is still suffering as a result of "hard disk drive supply shortages".
Numerous firms have encountered problems due to the tragic flooding in Thailand, where several computer manufacturers have plants.
Intel said that it expects the hard disk drive supply shortages to continue into the first quarter of 2012, "followed by a rebuilding of microprocessor inventories as supplies of hard disk drives recover during the first half of 2012".
Last month, technology research firm Gartner reported that shipments of PCs in Western Europe dropped over 11% in the third quarter of 2011, in more "unpleasant reading" for the struggling PC industry.
According to iSuppli, global PC shipments are expected to total 84.2m in the first three months of 2012, down from a previous estimate of 88m.
Today, Google used a special doodle on its search home page to honour Intel co-founder Robert Noyce, the man often referred to as the "Mayor of Silicon Valley" who co-invented the integrated circuit.