Pc wont turn on, fans work right after plugging it in

[Razorscootertotheank]

Hi,
I’ve been upgrading an old machine and today, now that I had assembled all the parts ir shut down and doesnt want to start, also before this it turned on but went to w8. As soon as I plug it in the all the fans and the power button turn on(afraid this is due to a fried psu?)
The CPU is an I5-4440, H81 mau board and it has an Rx550 2gb(previously a gt 630) and 8gb ddr3 ram (prevsly. 4 hd). Also has a new ssd as boot drive with w10 upgraded from w8.1) Ah and the psu is only 300w oem from asus
Sry for the long and not very clear explanation but I hopeu can help me

[phillpower2]

Sounds like something shorted out

A 300W PSU is too weak for a RX550 so before going any further with troubleshooting you need to get yourself a known good quality brand 400/500W bronze efficiency rated PSU, let us know when you have one.

[phillpower2]

Any update for us?

[phillpower2]

Thread closed due to lack of any feedback from the OP.