Question New CPU installed but won't boot into windows after Post.

[zytoei]

I just upgraded my CPU from a Ryzen 7 2700x to a Ryzen 7 5800x. My motherboards bios firmware is the latest it could be. The new CPU is recognized in the bios. But after restart my keyboards no longer work and I cannot get back into the bios upon post. Instead it just loads into a black screen and when I turn the pc off manually it instantly turns off. Currently the only way to get back into the bios is to reset the cmos. If I reinstall my 2700x there will be no issues which I can't seem to understand what is happening. I have an ASUS ROG Strix B450F Gaming Motherboard, 2x 16GB G-Skill Tridents, RTX 4060ti, EVGA 850P2 PSU.

 

[punkncat]

Is the keyboard wireless?

 

[steveb1976]

it could be "cms" compataability issue,, when oyu get into bios check if your " cms is set for " legacy or uefi" for other devices. this can sometimes be the issue". i had similar issue on my gigabyte b450m board. if this does not work. the other option is "to fl;ash back to a previous bios", (1 that still supports your new CPU

 

[Misgar]

I was testing a PC recently, fitted with a USB KVM. I could not get into the BIOS by pressing the 'Del' key until I plugged an old PS/2 keyboard into the rear panel. N.B. I did not disconnect the KVM or the USB keybaord and mouse, but left them connected.

Some computer BIOS take a while to initialize the USB keyboard (especially when connected through a KVM switch) and have finished waiting to see if you've pressed the 'Del' key.

Try a PS/2 keyboard if you have one and see what happens.

On another system, all I see at startup is a black screen (and a small flashing cursor) for 15 seconds, before the BIOS text appears. Then the Windows logo appears, plus rotating dots. Finally the desktop appears.