Area 51 R2 Motherboard stuck in Legacy

Hello! So yesterday I wrote that I could not update my bios and alienware went ahead and replaced my MB. The tech came out today to replace the mother board, However the new MB is stuck in legacy mode and every time it boots its goes to a dos screen and looking for a DHCP server. Im in the bios and I see its stuck in legacy but I cant change it. The tech went put the new service tag into the bios, We was able to get into windows by F12 and selecting UEFI boot to windows, but now when I try that it says windows had a problem and cant boot. Any ideas? Thanks! 

Edit: So when I hit F12 I can now boot into windows under UEFI but I cant still set UEFI as default boot.