Boot drive not seen

[Slykrana]

I just upgraded my mobo from asus prime b450m-a to an Asus tuff gaming b550m-plus.   After a few power problems i now have a booting issue my windows is on an m.2 ssd and is seen by the bios as an nvme however, it is not showing up under boot priority in the listed bootable drive.  In fact nonwle of my storage devices show up there.  I currently have my m.2 installed in the port with the heat shield that comes with the mobo and my ssd and hdd are on sata 1 & 2.  Please help

[Windows7ge]

Go to the Advanced Menu -> Boot and check weather or not Legacy Boot (sometimes simply called (BIOS or BIOS-CSM) is being permitted. It's possible UEFI wasn't used on the old motherboard. If UEFI is the only option set on this one Legacy Boot devices many not show up in your boot menu.

 

You can also check your CSM parameters somewhere under the same menu and see if they allow Legacy Boot.

 

If Legacy Boot is enabled but still nothing shows up we can troubleshoot from there. Screenshots are helpful BTW since every BIOS UI is different. We can't provide exact information unless someone else has your motherboard.