Secure boot is disabled and when I turn disable CSM my hardrive no longer shows up in the bios.
This doesn't matter if you have a UEFI installation, which for any system as new as yours you SHOULD have. With a proper UEFI installation the drive is not going to show up in the list of boot devices. Instead, "Windows boot manager" is what you should see, and that is correct for a UEFI installation. Otherwise you have a legacy installation, which isn't recommended, but here is what I'd recommend that you try to do unless you are happy to simply go back to the old CPU.
With the old CPU in, go into Windows and backup everything that is important and that you can't afford to lose. Backup your browser bookmarks, any important documents, files, folders, movies, music, etc. to another location like a secondary drive, external drive, thumb drive, optical disc or cloud storage.
Go to the Microsoft website and create new Windows installation media using the Media creation tool which can be found at the following link.
https://go.microsoft.com/fwlink/?LinkId=691209
You will need a flash drive with at least 8GB of space to create the installation media on.
Power off, swap out the CPUs (Might be worth mentioning here, because you never know, that each time you swap out the CPU it's probably a good idea to make sure you repaste) and then go into the BIOS. Make sure CSM is disabled and Secure boot is enabled. TPM does not need to be enabled for Windows 10 UEFI installation but it probably won't hurt to have it enabled either. Go to the exit tab and save BIOS settings. Depending, you may need to save and exit BIOS to do this, then go back into the BIOS and on the exit tab find the boot override option and choose the flash drive you created the installation media on. It should boot to the flash drive and the Windows installer should begin.
Then, follow this process, exactly. If at any point during the process there is a problem then there is probably a problem with the CPU that you bought used, because there would be no other reason at this point to still be having problems so long as there are no bent pins on the CPU since it works completely fine with the old CPU installed. Probably a good idea to read through my Windows 10 clean installation guide at least once, maybe twice, before you begin any of this process, just so you are completely familiar with the process as I've outlined it.
If you are looking for the Windows 11 Clean install tutorial, you can find that here: Windows 11 Clean install tutorial (Click here) Otherwise, welcome to the Windows 10 Clean install tutorial This tutorial is intended to help you, step by step, to perform a clean install of Windows...
forums.tomshardware.com