I recently converted my disk to GPT in anticipation of Windows 11, went smooth. I just did the same to my wife's PC and now it boots to a black screen that says "Reboot and Select proper boot device or Insert Boot Media in selected Boot device and and press a key...". It will not allow me into the BIOS to change the boot device to UEFI. I've keep tapping Delete after turning on, but no luck. After I did my PC I could go right into the BIOS and make the change. Right now I'm just stuck and can't seem to get anywhere.

MSI B450-A Pro Max AMD AM4 ATX Motherboard
AMD Ryzen 5 5600G
SanDisk SSD