It just shuts down after 30min or 1 hour

I have same problem and it happened from day ONE. Have shipped it to repair numerous times. They have replaced everything they could think of and it STILL does it. You can try all those things, none will work. I eventually just had to buy a new laptop because after over a year of reapirs, they said out of warranty. They wouldn't even give me a small credit towards a new one. I was NOT amused.

check if the fan is working properly, the place you use your laptop, must have breathing space, for ventilation, e.g, if you are using it on bed, then place somthing underneth, if all these are fine, then check out your battery, or cmos battery, could had gone bad in times of using..last options are RAM, PROCESSOR..

check the battery if possible run it on only AC