G Scott bought a Sony Vaio about a year ago, and he's been getting random shut downs. Leo says it sounds like a heat issue. Computers will shut down as a safety measure when a processor begins overheating. The fan has stopped running. G. Scott should go to CPUID.com and download a motherboard monitor to keep an eye on it.
On eBay, he can also buy a USB laptop fan that can blow air over the bottom of a laptop to keep it cooler, since laptops are notorious for generating a lot of heat. He should also check for dust or blockages. The thermal paste on the processor could dry out and separate from the heat sink and that could cause overheating as well.