I have a dell dimension E510 with windows 7 ultimate 64bit. Recently my pc keeps going off after being left on for about a day. I would usually just leave it on indefinitely unless i had to reboot or for some other reason but as of recent it stays on for about 12 hours max and jus goes off with a blinking amber light. I then have to put it off by pressing down the power button for a few seconds and leave it off for at least about 6-12 hours and if i do try putting it on too early it will go on but just shut down with the blinking amber light after a few minutes. I'm not sure whether or not this is an issue with the motherboard or the power supply. I recently had my motherboard replaced due to the pc not going on at all. Any help would be greatly appreciated. Thank you in advance.