I just bought a new Dell Latitude E5470. I've had it about 5 days. It has been working since I got it. Today I was playing with the power settings. I don't think changed anything but the Sleep setting when on battery power. It had been on AC all day. This evening, I happened to hover over the power icon in the taskbar. It said something like "On AC, 71%, not charging". This was surprising, because it was plugged into the AC and the adapter light is clearly on. Then I noticed that the hover message was alternating between "Not charging" and "Charging".
As a test, I went to the AC outlet and unplugged the adapter. The PC immediately powered down. Why did it do that? Did I change some setting accidentally that cause that? I plugged it back into the AC and powered it back up. After about 5-6 minutes, the PC went down again while I was using it.
This happened 2-3 times, so I closed the lid and went to do something else. I just came back, opened the lid, and powered it up. I got a message that said something like: "If a service update was just installed, I should power down, unplug the AC adapter, replug the AC adapter, and power back up. I did that and it seemed to come back up again.
Can anyone explain what is going on and how I can fix it?