My Dell Inspiron 15R 5521 laptop turns off suddenly at random times

I have a Dell Inspiron 15R 5521 laptop that is 7 years old now, its running Windows 10. It just starts to turn off suddenly at random times without any warnings, when I power on again, starts running fine. It doesn't turn off when I run many apps, its completely random. The Event Logger shows The previous system shutdown was unexpected error Here is what I have tried Removed battery, changed power adapter as well Cleaned up its fan Tried to shake and move laptop but it doesn't turn off, thinking maybe something loose inside Been using cooling pad since I bought laptop, and laptop doesn't see t

Question by Umair Ayub on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.