Question My old computer when turned on it turns off and restart itself

Jun 28, 2022
I use an extremely old pc, I played some pretty light games there, and normal stuffs happens, the pc working, i can play games. Then I shut down the pc since I'm going out for dinner.

Then after I'm back, I plugged the monitor and pc like normal, but when I started the pc, fans turning on, the light turns on, like normal.

But the monitor didn't recieve input and my pc light turned off after like 2 sec from me turning on.

Then the fan stopped, and after 3-5 seconds it starts to turning on, but it loops (no input, fan and light turns off, start again and loop again).

It loops for a bit now, so I unplugged the pc, wait 5 mins, tried again, but it still happens

And I did nothing like changing parts or move things, its just like old position that works fine!

And I dont really remember my pc specs, all I remember is 1gb ram and i3 2nd gen and extremely old parts that's been untouched for years I think