Question Pc won t boot , it keeps restarting

[ReMixaTu]

My old pc is not working when i used it it got a bsod and never started , i cleared cmos , replaced the battery ,changed ram slots , tried starting it without the gpu , the psu fans spin when it s not connected to the mobo , if i manage to find a bios speaker , should i be able to tell what s wrong with it , how can i find if the psu is not giving enough power to start ? Thanks!!

 

[Dexxly_uk]

Is there any thing wrong with your 24pin slot or conector?

 

[ReMixaTu]

I left it not all the way in but the pc does the same thing as before , it s making contact , it s a space under the mobo where the connector is and my mobo is flexing any tips to plug it in all the way after i finish repairing the pc ?