Turns off and then on automatically and again off

[axyz]

Hi, my cpu turns on automatically and then off without even booting up completely, and then after some time it turns on again. Its acting up like this since last few days and I dont remember of any incident particular to this. When I disconnect the wire from the mother board it can stay on without turning off.
can any body help me what is the problem?
Thank you

[stroyal]

Welcome to TechIMO!

If the wire you are disconnecting from the motherboard is the start button, then I would strongly suspect the power switch/button.

To test this, use a screw driver or something similar to connect the 2 pins that the power switch/button connects to, then quickly remove it. If it works normally, then you need a new power switch/button.

I would also test the switch, to verify that it is sticking in the on position. The switch is a "normally off" switch/button.