My Toshiba Equium A110-252 keeps turning off. When I try to turn it on, it turns off again. It can run for unspecified period of time (a day, a week) and one day it just turns off and it is impossible to run it normally (keeps turning off). When it happens, there is no sound, that fan is working. It is dead silent. When it happens, I noticed, that laptop turns off, I suspect, from overheating. My operating system was always windows xp (original Toshiba xp version), but I have lately tried windows 7. It worked fine, but only for a while. Later on I started having the some turning off problem. I reinstalled windows XP again. It worked almost 1 week for me fine, but later on the same problem. Fan is completely clean, RAM is fine, charger and battery are fine. My guess is, that fan is breaking up from time to time. Is power supply fan a different part of the laptop or it‘s the same fan? Second, it could be main board's failure. Is it worth replacing fan or main board?