Question PC boots up fans start up but no display and usb ports not working

[IMSOOASIAN]

Ive been going at it for a few hours now i cant figure out the problem ive double checked everything after installing a new cpu and heatsink

My specs:
B450m DS3H WIFI
AMD Radeon Rx 580 4GB
Ryzen 5 3400g 4-core 8 thread
sadly i dont know what kind of power supply i have as it was prebuilt

 

[Phaaze88]

Was the motherboard's bios updated before installing the new cpu?

 

[IMSOOASIAN]

Was the motherboard's bios updated before installing the new cpu?

im completely new to this so i dont really know i got the motherboard a few days ago from amazon before i started installing yesterday

 

[Phaaze88]

im completely new to this so i dont really know i got the motherboard a few days ago from amazon before i started installing yesterday

Then that's your problem. Options are:
1)Return the mobo and get an X570 model, get a B-series with a bios flashback feature, or grab one of Msi's MAX motherboards
2)Take it to a nearby PC shop - or, if a friend has an older Ryzen cpu - and ask if they can update the bios for you
3)Request a boot kit from AMD: https://www.amd.com/en/support/kb/warranty-information/rma-form

 

[Firsttry51]

just had a no post problem with a B450m DS3H and a r3 3200g, turns out it was the ram that didn't work with that specific cpu
the ram worked fine with my r5 1600 on the same board but didn't post at all with the r3 3200g
i took the ram from my current rig to test it and it posted fine with the r3 3200g
so test it with another ram model/brand just to be sure