i cannot return it, it has more than a year!

it only works when i turn the air conditioner on, and no, the processor is not overheating. so strange.

i use it mostly for 3d rendering, so i leave it running for hours at 100% processor speed, many times a week, i usually left it running at night with the air conditioner off without any problem before, but now i have leave the air conditioner on when i leave the computer on at night. It still shuts down with the A/C on but much less frequently.