Memory Reference Errors/Hard disk no longer detected?

So i just received by repaired Mobo from asus and after i reinstalled it suggests I update my bios and to press F1 (i didn't update my bios) . After It booted the OS (everything booted up fine) I went to shut down the PC about 10 memory reference errors kept popping up. Now when I try to boot up the OS "im getting the reboot and select proper boot device or insert boot media in selected boot device and press a key" Its recognized in the BIOS? I am thinking i need to update the bios? or maybe a clean install of windows? Any help would be greatly appreciated.