Chosen Solution
Why won’t my camera turn on when I press and hold the power button?
The camera most likely will not turn on because the battery is dead or because it has been inserted incorrectly. Try recharging the battery and then carefully inserting the battery back into the camera. To insert the battery correctly match the orange part of the battery with the orange part of the camera.
I noticed environment temperature affect this - a month ago it could be turn on in temperatures below 20°C, now it requires below 18. But (1) I cannot take a refrigerator with me, and (2) after taking it from the refrigerator water wapor condensates on it, especially on optics, making it unusable.