Strange problem with my PC

[Tomy]

Hello guys,

I have an old spare desktop PC. I'd given it to my brother but when after one week I got back it and turned it on I saw messages of the below screenshot!
It turns automatically off after 15 seconds or less!
What is the problem with it? Can someone please help me?

 

[Tomy]

For clearing the CMOS, I put the tiny plastic for connecting pins no 2,3 (as it has been written on the mobo next to the jumper) and now the PC is on. But since I did that work for clearing, no hardware seems to be working. I waited for a while and returned the jumper into normal mode.
Now the PC is on but on the contrary to the previous situation, no message comes up. The PC is working but shows nothing!
The problem is that I can't enter to the BIOS.
It's very odd. It seems to be a hardware issue.