A few weeks ago, my personal laptop battery began acting screwy. It wouldn’t take a charge unless the battery were completely drained, nor would it run on AC power unless I let the charge completely deplete and then sit for many hours. I figured the problem was with the battery itself, as the computer’s two years old and for a few months has not been able to hold more than an hour’s charge, so I ordered a new battery. This took a few days to arrive, but as I have my work laptop and personal desktop, it was no big deal.
The other day, just before the new battery arrived, I had occasion to use the personal laptop, which had sat idle for a few days and thus had an utterly drained battery (and so would accept AC current as long as I didn’t unplug it for even a few minutes. After doing that little bit of work I decided to run MalWareBytes: not the regular quick scan that I run every day I use the computer (which completes in under 10 minutes) but the full scan that takes over an hour. I also update MalwareBytes and my other anti-malware software every day, incidentally. MalwareBytes found a trojan, which I naturally quarantined and deleted. After doing this, the computer’s power system began acting normally again. Well, semi-normally, anyway; the battery would still only hold about 30-45 minutes charage. But there was no longer any issue with AC power.
Could the trojan have caused the problem?
ETA: I installed the new battery , as I’d been expecting the old battery to die on me anyway.
When you weren’t using the computer how “shut down” was it? Did you use Shutdown, Hibernate or Sleep mode? (I’m assuming Windows OS.)
What I’m getting at is that if you were not 100% sure that the computer was completely off it’s possible that you might have had a malware that was doing something in the background and that could have accounted for low battery. I have no suggestion on why it wouldn’t charge properly.
And, come to think of it, even if you did a “shutdown” command, many computers can be woken up by a program which might have been running when you weren’t watching it. This can be done through a scheduled task or using some BIOS commands (Wake on LAN as an example).
So the bottom line is that it is possible–even if that’s not what your problem actually was.
At first Hibernate. I don’t use that laptop every day, or even every other day, and it’s my impression that Hibernate is meant for cases in which the computer will be idle for a few days at a time. When I became aware of the problem I started putting it in Shutdown mode, but that didn’t do any good; the battery would still have to drain completely and then the computer sit idle for many hours before it would start accepting AC current.
I never use Sleep for the personal laptop, though I often use it for the work unit.
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I thought Wake on Lan only worked if the computer were in Sleep. But, at any rate, I went into BIOS years ago and disabled that.
Me too. And you know what? Every once in a while I find my computer (that I know I shut down) powered on and sitting at the startup screen.
I found this on Wikipedia:
I don’t know why and I haven’t tried to see if it’s trying to communicate with the mother ship by leaving wireshark running on my network. Instead I put the computer and monitor on a switched power strip and (when I remember to turn it off after use) the problem goes away. More accurately, the problem is hidden from me, but that’s acceptable.
(Every malware detector I’ve tried says my computer is clean so I’m at a loss as to what does this. I suspected a power line glitch might be doing it, but I added a UPS and it still happened.)