Usually that indication means that there is a problem with the motherboard. Unlike desktop systems, there is no separate power supply in a laptop. All of that circuitry is on the motherboard. It could be the dc jack on the laptop but not likely. The following should offer more information.

https://www.dell.com/community/Laptops-General-Read-Only/Charger-light-goes-off-when-I-plug-it-into-the-laptop/td-p/3953115

Welcome to the Dell Community  @Vaiya 

The only thing I can think of is "Shotgun" it !!!

Disconnect any peripheral device attached. "Printer, External Display etc."

Disconnect the Battery, HDD/SSD, CD/DVD, WiFi card, BIOS/RTC battery and memory.

Then connect the AC adapter.

If the light goes out then it is definitely the system board.

If the light stays on then replace one device at a time until the light goes out.

EDIT: Make sure to disconnect the AC before connecting a device.

Best regard,

U2

To better assist you, we would need the exact model number of your laptop/desktop???

Is the laptop still under warranty???

PLEASE DO NOT POST ANY SERVICE TAGS!!!

Try the steps that U2CAMEB4ME has suggested. You could also try a reset. Disconnect the battery and unplug the adapter. Then press and hold the power button for 30 seconds. Reconnect everything and try again.