Question No hdd light, no display

[Claszureme]

I recently changed my 700W PSU to 500W PSU and also my video card(RX570). My pc was fine(old parts) in this morning like I played games and stuffs before these things happened. When I turn on my pc, everything is fine inside of it except my hdd light that will turns on and off, and then no display ofc due to no hdd led. It turns on for 4-5 seconds and then off meaning there would be no display.
I tried these solutions below:
-reset CMOS
-trying every HDD cable.
-removing the video card, and using the MoBo
-unplug and plug RAM sticks
What should I do? Thanks

 

[Lutfij]

When posting a thread of troubleshooting nature, it's customary to include your full system's specs. List them like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:

You should also mention the make and model of the two PSU's you've worked with and the age of the 700W unit. What was your card prior to the RX 570?

 

[Claszureme]

Cpu: A10-7850k
Motherboard: asus a68hm-k
Ram: Kingston Value ram 4gbx2 1600Mhz ddr3
Hdd: WD Blue 1TB
GPU: Palit GTX 1050Ti(old), MSI Armor RX570(8G)
PSU: 700W Class A PSU(old), 500W Silverstone ST50F-ESB
Chassis: Rakk Anyag
os: w10 64bit

The age of 700W psu is about 2yrs+ and the new one is just bought 2nd hand(looks like bnew) in some pc store in japan.