I just installed a new motherboard and cpu and it won't let me boot from the USB that I made into a boot drive with rufus. It says I cant install it to my hard drive because it has an MBR partrition table.
UEFI-based systems, by specification, can only boot from GPT-style disks. The traditional BIOS can boot from MBR-style disks.
I recommend deleting all existing partitions on the drive so you will be starting with an empty drive. The Windows installation will make the partitions it needs and format them without any help.