Question New build won't boot

[Danwliny]

New Asus b450m-a ii and cpu and ram. The hard-drive and gpu are from an older system. The only way it will turn on is to jump the power pins on the board. Get a message to insert a boot disc. It runs and ends up at "Free dos" and a c:\> prompt. I do not know what to do. The old hard drive worked fine in my old system as did the gpu. I have windows 10 on it.

 

[DSzymborski]

Let's get the full, actual specs, not just a motherboard name and then generic references to parts.

And you're likely looking at a full format and install of the OS drive. Windows is not a modular OS, it just tries when people cut corners instead of doing things properly.

 

[Lafong]

You don't state that you did a new Windows install, so I'll assume you did not.

A simple move of "old drive" to a new system with new motherboard, new CPU, and new RAM is quite likely to be a problem. No surprises.

You can cut your losses and do a clean install of Win 10

or

Spend X hours trying to solve the current issue without ever knowing if more problems might arise next month.

What was the old motherboard and CPU?

 

[ZeroTwo.02]

better reinstall your operating system.

if you don't wan't to.
try enable csm on bios, save config & see if you can boot to your disk OS with legacy mode.
to enable csm you might have to disable secure boot too.

if you manage to boot to windows, you need to uninstall old mainboard chipset drivers, old audio driver, and old gpu driver. then install correct driver for the new hardware.

if you still unable to boot to your os, seems like reinstall operating system is the only way to fix it.

before reinstall os, return you bios settings back to UEFI / CSM disabled.