New Ryzen 5 pc build not booting up

Well I’ve decided to bite the bullet and build my lad a new pc for his birthday. All was going well until I attempted to boot the pc - nothing.

CPU = AMD Ryzen 5 3600. Mobo MSI B450I Gaming Plus AC that had been flashed to a Ryzen 3000 series using a Ryzen 2600 cpu.

I cannot post a screen shot as there is no output from the mobo to my monitor.

Gutted. Confidence knocked! Can I have some help please?


Active Member
So the pc was working with the older CPU you flashed bios pc still working at this point? Or just not working with the new CPU?


Active Member
When you say nothing, what are we talking about? Any lights on the mobo at all?

Does the mobo light up but you get no output on the monitor?

Can I double check the PSU is definitely switched on (switch at the back where the kettle lead goes in) and connected up to the motherboard (both the 8pin CPU cable and the big-ass one that goes next to the SATA cables).

Also, can you please name all the components that are hooked up at the point you're attempting to switch it on?
All lights on. No power from mobo to monitor. PSU connected to mains and switched on.

800w PSU (overkill I know. But it came as a package with the RAM).
128GB nvme ssd
Palit GeForce GTX 1050 gpu


Active Member
The lights on the motherboard will indicate what is wrong (or even that it thinks everything is fine), have you grabbed the manual (physical or just google it) and checked what the lights indicate?

Also, just to triple check the basics: the monitor definitely switches on and displays no input detected or something similar? Have you set the monitor to use the input port you’ve plugged in (e.g DisplayPort, HDMI etc)? Have you plugged the other end into the GPU directly (not the motherboard if it has a port)?


Well-known Member
If your CPU fan is spinning it's likely as hamzatm says something to do with the display output. Try plugging the HDMI cable direct to the motherboard. At worst I would take your GPU out, reset the bios and then connect the monitor direct to the m/board to see if you get an output to the monitor.


Active Member
Take it back to basics.
Do you get any monitor out put with nothing else plugged in no drive etc and just the CPU and memory.


Well-known Member
The CPU does not have onboard GPU so there will be no output from the MOBO connector - it's not an Intel CPU!


Well-known Member
OP, you have connected your monitor to the Graphics card connector and NOT the motherboard connector?


Well-known Member
If your GPU has power connection sockets, have you connected them to your PSU?

If that's not the issue, try re-setting the BIOS using the jumper pin on the MOBO.
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Active Member
if the vga light is lit and its connected to the psu if its needed, the gpu is faulty. the other thing is the psu may have a faulty 12v rail to the gpu. thats a posibility.
Hi guys (n gals?).

Apologies for the slow reply.

Via a process of elimination. Fault eventually traced to a duff CPU.

New CPU purchased and new build booted from the word go!

Thanks for your input everyone!


Well-known Member

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