Acer 4810T "Plugged in, not charging"

My mum has an Acer 4810T and all of a sudden the battery(seemed to) stop working about 10 days ago. She knocked the power cable out and the laptop turned off, that's how she came to this conclusion. This happened a couple of times, she got frustrated and bought a new battery.

The new battery arrived today, so I plugged it in, and it's got the same problem. The old battery is stuck on 97% charge with "plugged in, not charging" stated after that(seen here.) New battery is on 40% with the same situation.

Virus scan brings up nothing, I tried reinstalling the drivers and nothing changes. Cleaning the connectors didn't make a difference. Google brings up the same issue affecting a few others, but no results or solutions. Has anyone managed to fix something similar?

Bonus info:

OS: Vista

Age: About 2 years old

Windows: Up-to-date