1. make sure there's no dust
2. make sure you're not cover up air vents with clothing/carpet/blankets
3. make sure you're not trying to run your computer full speed in a 80F environment
4. make sure ALL the fans are working properly (check with speedfan/hwmonitor)
5. the only other thing I can think of is your thermal paste dried out and needs to be replaced.
The fan and air vent are clean. Thermal paste is ok. But when i start the computer the temperature rised rapidly. I've check with hwmonitor, the result shown above 75C for all component when idle in 10 minutes. even in battery or DC connected.
if even the thermal paste is ok then maybe it's a faulty temp sensor? but on all devices...
what is the CPU/HDD/GPU load when it's idling?
what temperatures does everything start out at?
Perhaps your power supply gone broke and providing bad power to the components so they start generating extra heat or one of the components is responsible for all the heat in the case (maybe faulty motherboard)?
Is it possible caused by some programs running above normal at the background?
it's possible, but it would be reflected by your cpu/gpu/hdd load. If the background process is taking up a lot of resources then you will see cpu at a decent load even while idling, which in turn can contribute to temperature rise, but again, unless it's 80-100% load while idling it shouldn't be heating up all that much unless your cooling system isn't functioning properly.