Question Dell optiplex 745 not turning on

[Anouar1710]

Hello,
I've got this problem with my dell optiplex 745, when i plug in the power cable it tries to turn on without clicking the power button and shuts down after, and when i press the power button it turns on for 4 or 5 seconds and shuts down after, sometimes it turns on for half a minute or so and thes shuts down.
After that the pc gets stuck on a loop of (power on and off)
If anyone has a solution please help.
Thanks

 

[hang-the-9]

Power supply or motherboard are the top 2 things.