Alternative way to boot to CD?

My Asus mobo has very unresponsive firmware. It takes next to forever for the first menu to appear, and what's more, it periodically forgets its settings and reverts to default.
So, this morning my Windows boot got borked, and I wanted to run a live CD in order to fix it or to do a system image restore.
Is there an alternative way to coax my computer into booting from the CD drive, without accessing the firmware menus?
I tried switching the SATA cables, but it still recognized my borked hard drive and threw an error. I tried disconnecting the hard drive, and that works, but then when I reconnect it, the rescue environment doesn't see it, so I still can't fix it.
Any ideas, besides replacing the mobo?

That sounds like your BIOS/UEFI settings battery needs replacing.

A very cheap and easy job on a Desktop. If it's the one you have listed in your specs then it should have lasted 5 years or so, maybe it was just a bad battery, got too much heat.

Helmut said:

That sounds like your BIOS/UEFI settings battery needs replacing.

A very cheap and easy job on a Desktop. If it's the one you have listed in your specs then it should have lasted 5 years or so, maybe it was just a bad battery, got too much heat.

Thanks. I guess there is hope, after all.

If your BIOS isn't saving the settings, you may need to replace the motherboard battery. But as far as booting from your CD drive, there should be a boot option menu in the BIOS to override the boot order and you can choose to boot from CD drive, USB, etc. instead of trying to boot from SATA HD. You should be able to boot from CD while the SATA HD is still connected. Also some BIOS have the option on SATA to allow them to be hot plug connected after booting system and they will be recognized by Windows, but you have to change SATA port to "Hot Plug" for it to do this. Maybe this might be worth trying.

Maybe the BIOS battery is failing, although they are typically good for years. The manual doesn't specify, but if it's a type 2032 button cell, that is one of the easiest to find a replacement for.

Aside from that, you can also change the boot order on a one-time basis by pressing the F8 hotkey during boot.