Can’t get to post

[Archemas]

So I’m building a computer for a friend. Everything looks to be in order but I can’t get the display to show anything. The build is an: 

 

CPU: i5-9400f 

Motherboard: Asrock B365M Pro4 

GPU: Rx 580

RAM: 1 stick of Corsair 16gb
storage: Samsung 500gb evo ssd 

Power supply: corsair CX550M
 

I tried everything from the main thread but no joy. I have rgb and fan spin even on the gpu so I think that’s good there. I have a suspicion it’s the PSU. When I start it up it turns off for about 2 seconds and turns back on on it’s own but still no post. Can anyone confirm or know anything more to help me out? 
 

Edit: I also should mention I don’t have any sound come out of the device either. No beeps or anything. Just the fans spinning. 

[AndreiArgeanu]

Have you tried moving the ram stick to different ram slots and booting up with it?

[Archemas]

1 minute ago, AndreiArgeanu said:

Have you tried moving the ram stick to different ram slots and booting up with it?

Yes I tried the each end I haven’t tried the inner ones though. I can do that but should I do it with or without gpu? 

[AndreiArgeanu]

1 minute ago, Archemas said:

Yes I tried the each end I haven’t tried the inner ones though. I can do that but should I do it with or without gpu? 

Try the inner ones with the GPU, the i5 9400f has no on board graphics.

[Archemas]

3 minutes ago, AndreiArgeanu said:

Try the inner ones with the GPU, the i5 9400f has no on board graphics.

Wow. I um...I can’t believe that worked. Thank you. Do you know why? 

[AndreiArgeanu]

3 minutes ago, Archemas said:

Wow. I um...I can’t believe that worked. Thank you. Do you know why? 

Probably has to do something with priority. Like, for the pc to work you must fill the slots from slot 1 to slot 4, so you start with the first stick in slot 1, then the 2nd one in slot 2 and so on, doing otherwise causes issues as you can see. It's just a thing that happens.

[Archemas]

Just now, AndreiArgeanu said:

Probably has to do something with priority. Like, for the pc to work you must fill the slots from slot 1 to slot 4, so you start with the first stick in slot 1, then the 2nd one in slot 2 and so on, doing otherwise causes issues as you can see. It's just a thing that happens.

Well hey I appreciate it. You were super quick to answer too and I appreciate that a lot because this was time sensitive. Thank you so much!