BIOS won't save boot sequence

[DavePro305]

I just bought a new USB external drive that will always stay connected. The problem is, now my PC tries to boot from it from the start. I went to the BIOS and changed it back to my internal HDD as primary boot disk. I then press "save changes and exit" but, even if the BIOS confirms me that I changed the boot sequence, it changes it back again as my external HDD as primary. I tried restauring to default but it does the same. Every other change I make in the BIOS is saved correcty but not the boot sequence. What is happening? (my motherboard is a Asus M5A97)

 

[corroded]

Unplug it, boot up and restart a few times, leave it unplugged and go into the BIOS and set the boot order, remove the USB HDD/Floppy settings.

Restart again and AFTER restarting plug in the external. Once usable, shut down, then start up again... What happens?

Also, Is there a bootable partition on the external? Was it a conversion of an older system into an enclosure?

 

[DavePro305]

Nope. Nothing works. I rebooted, removed, reinserted as you said but it still does the same. There is no bootable partition on the disk and it is not a conversion of an older system, it's a new Seagate USB back-up drive.

 

[DavePro305]

I also tried switching USB hole... just in case

 

[corroded]

Bizarre... Also look in the BIOS for USB boot options, might be a way to just disable non-internal boot. Just another possibility. It used to be an option in some BIOS