ASUS X75V series shutting down while lid is closed sometimes

[svorcs]

I own Asus notebook and running windows 7 on it,
specifications: intel core i5-3230M 2.6GHz, installed memory (RAM) 6GB, Graphic card: Nvidia Geforce 740M. Machine is about 4 - 5 years old,
I'm experiencing sudden shutdowns, but when i'm not using it.
It turns off on it's own after being left idle, and everytime before it shuts down i hear ventilators go very loudly: vuuuuuuuuuu for about a minute, after that shutdown, then i got to turn it on again. Also my battery may be bad or something, because there is orange light beeping all the time, like it didn't ever before. no green light anymore. I tried to reset power options to default but hasn't come up with a solution.
If anyone knows what could be wrong?

Apologies for lame english.

 

[webworkings]

I would start with replacing the battery. Also, try monitoring the temps to see if anything is overheating.

 

[Captainawzome]

In addition to checking the battery, I would also take a look at the thermal paste on your GPU/CPU and try replacing it. If you haven't taken apart your laptop there are many videos online on how to do it. While you have it disassembled I would also try cleaning out your fans/heatsink with a compressed air can, or if you don't have that use a rag to get it out. Good luck and keep us updated.