I have seen this a lot of times over the years. The cheapest thing it can be is an old CMOS battery.
Can you reveal more about this laptop?
Hi, guess I'm more just wondering if anyone's had this issue before? My laptop turned itself off while I was using it a couple months ago. It wouldn't turn back on for about a week. Just as I was taking it to get repaired I tried it, and it turned on! Since then it's been repeating this behaviour. Sometimes it turns itself off. Sometimes I'll shut it down properly, but it won't turn back on. Have to wait anywhere from a few minutes to a week +/-Charger led on laptop won't come on when it's being weird. But I can hear a soft whining sound when I plug it in. I've changed all the power settings, logs just mention kernel errors. I'm assuming it's hardware. But why does it work sometimes? It's very frustrating!!

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