Old laptop keeps turning off

[Pedro_35]

I have an old Inspiron 1525 and it started to turn it off by itself. I opened and cleaned the heatsink, but it keeps shutting down a few seconds after being turned on (something like 30s). I even tried to use the bios diagnostic, but it shuts down during the tests. I`ve tried to change the power source with no sucess.

any ideas?

 

[Saga Lout]

Have you tried removing the battery and running on mains electric power alone?