>>The laptop is Dell. I didn't want to re-start, because I have about 5 different apps running and also about 15 different tabs opened in Google Chrome.
>>
>>If there is no better option I'll shutdown.
>
>Operating system?

Windows 7.

Here is the advice I got from the Network Admin

Make sure that the cable from the wall is firmly plugged into the power supply. Sometimes it looks like it is connected but is a bit loose. If that's not it, power off the system, remove the battery and the power supply, then press the power button to drain any capacitor power from the system. Plug the battery and power back in and see if it recognizes it. Let me know how it goes.

But I'm not sure what does it mean here - remove the battery. How exactly?