Be on the lookout for a worm that causes your CPU fan to stop working, leading to overheating. Since the worm is an actual earthworm, the threat of it spreading is minimal ;-)

Computer technician Sam Robinson, 28, who discovered the worm said: "The machine was displaying a message saying that the processor fan was unworkable. "I took the back off and had a look inside. Then I spotted what at first I thought was some sort of hair band or elastic band wrapped around the fan. "I soon discovered that it was a worm which had been burned to a frazzle. It had obviously wrapped around the fan when somebody had turned on the computer and caused the breakdown due to the fan jamming. "The vent in the side of the laptop was larger than normal and there was obviously enough room for the worm to get inside. "Needless to say I hadn't come across a problem like this before but was happy to sort it out for Mark."