Windows XP Home Edition Sudden Shutdown

I’v recently doubled the RAM memory on my desktop computer from 512 to 1024 and I experience sudden shutdowns. I can’t make anything from the “reports” so I don’t know where to start. Could it be an overheating problem?

Processor: AMD Duron 1600mhz (12×133), Motherboard: DFI AZ30-TC/TL (3PCI, 1AGP, 2DIMM, Audio, Video)
DirectX 4.0900.0904
Motherboard Chipset: VIA VT8375 ProSavageDDR KM266
Graphics Card: S3 Graphics ProSavage DDR 32 Mo
3D Accelerator: S3 ProSavage DDR