I have a Sony VAIO laptop that I've bought with a safe recovery partition, but later deleted it and installed a different Windows XP version so that I use the whole hard disk size. Since the computer doesn't save power when it's not directly plugged in an electric source, it doesn't reduce the brightness, just displays the same brightness. It also overheats in the area around the fan. Now, I don't know which software should I install so that it can save the power again before the battery goes wrong.