My laptop discharged when it was plugged in

While browsing web sites, I suddenly got a message that the battery is at low charge level. I looked at system tray, but it indicated that the laptop was plugged in. But after a while it switched off due to insufficient power. I charged it up in turned-off state as it could not boot up initially, and then boooted up.
My system settings power tab shows abrrupt charge loss over a few hours and also that the main power user is Windows File Explorer at 32% of power consumption share. What it could be?

Failing/Failed power adapter. Replace.
Failed/Failing battery. Replace.

EDIT The plugged in indication could just mean the device recognises a connection. The power icon in the SysTray should indicate that it is actually charging up and/or the time left to full charge.

idgat said:

Failing/Failed power adapter. Replace.
Failed/Failing battery. Replace.

EDIT The plugged in indication could just mean the device recognises a connection. The power icon in the SysTray should indicate that it is actually charging up and/or the time left to full charge.

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I looked at tray, it indicated that the computer was connected to the power supply.

Anixx said:

.... also that the main power user is Windows File Explorer at 32% of power consumption share.

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Does it actually say Windows File Explorer, or just Explorer (which is the whole OS)?

Anixx said:

I looked at tray, it indicated that the computer was connected to the power supply.

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But did it indicate actually charging and/or time left to full charge or fully charged?

idgat said:

Does it actually say Windows File Explorer, or just Explorer (which is the whole OS)?

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It is visible on the screenshot, it said "Explorer".

idgat said:

But did it indicate actually charging and/or time left to full charge or fully charged?

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It did not indicate charging, it showed plug image. I do not remember but it seems it indicated time till turning off, at least I received a message that the computer has charge for a few minutes.

Anixx said:

It is visible on the screenshot, it said "Explorer".

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Which is in Cyrillic script, but anyway, Explorer =/= Windows File Explorer (which is just a single program)

Well. I think the both names mean the same program (which is taskbar and file manager).