Dell will contact you over the coming weeks for a free replacement if you bought a new XPS 8300, Vostro 460, Alienware Aurora computer or Alienware M17x R3 laptop before 1 March.
Sandy Bridge is a new high-speed processor from chipmaking giant Intel. The fault affects an Intel 6-series support chip on the motherboard that sits alongside the Sandy Bridge chip, called Cougar Point. There's a transistor inside Cougar Point chips that can't cope with the voltage being zapped across it, and could degrade over time. That means bits of your computer could eventually stop talking to other bits, such as your hard drive. The fault could cost Intel $1bn.
Dell stopped selling the affected machines back at the start of February, and has presumably spent the last two months staring at the amount this is going to cost and weeping softly. Anyone who's bought an affected machine has been able to return their computer under the usual warranty, but if you're keen to hang on to your Sandy Bridge computer, Dell will now replace the motherboard.
Dell stated when the issue was first discovered it would wait for replacement chips from Intel, although other manufacturers have managed to be quicker off the mark with replacements. HP, Lenovo, Asus and MSI have also been affected by the problem.