Previous Pop! OS/Windows dual-boot broken after I removed the Windows drive

A couple years ago I set up a computer build with an ASUS motherboard for running POP! OS. Then, shortly afterward, I purchased a second hard drive, and I installed windows on it for a dual-boot, using windows bootloader. The problem, now, is the Windows drive got broken, and when I try to boot to just the POP! OS installation the only option to boot to in the BIOS is windows boot manager, and when I boot to it I get a blue screen, and some options, but no matter what option I choose, they all just reboot the system and repeat the process. I am wondering is there a way I can revert to a normal boot using just the POP! OS grub as it was before? Someone else on this forum had a similar issue: https://unix.stackexchange.com/questions/688253/windows-breaks-bootloader-in-dual-boot-with-pop-os but their problem is currently unresolved. Any help is appreciated!