Hi @MoaMetlFan  thank you for sharing an introduction. The AC adapter has many on-board fail safe attributes that reset when fully disconnected, but in this instance it appears to have suffered a CATastrophic failure. Guess that the dc power cord LED did not reappear when ac adapter plugged back into the ac mains socket (and not plugged into the m15 R3).  

When the LED at the end of the dc power cord does not reset, it could be one of more of the following:-  

1. the ac power plug that goes into the ac mains socket on the wall, has blown a fuse (replace fuse in ac plug did not reinstate LED),
2. ac mains cord plug not fully engaged in ac adapter's socket (check engagement and remove any moisture did not reinstate LED),
3. the dc plug has a short (remove moisture did not reinstate LED),
4. the m15 R3 external socket and internal cable assembly has a short (remove moisture did not reinstate LED),
5. the ac adapter has an internal fault and is dead,
6. other fault. 

Having already decided to replace the m15 R3 Power Adapter (130W, 180W or 240W), or have a look at its label to check its dc output voltage and dc plug size. It would be good to get a similar OEM ac adapter, but if playing power hungry games this is an unexpected opportunity to get a more powerful ac adapter with an increased dc output current (A). 

Search online in Canada for "Dell Alienware m15 OEM ac adapter" to see what is available.