Bios Not Showing Boot Devices

Not sure if this is software or hardware related so I'm just posting this here. I'm working on a Gateway SX2110g-UW308 running Windows 8.1 that has a number of problems, but for this thread I want to get my boot devices to show up in the BIOS. When I first started working on it everything was fine. I reinstalled the OS from boot screen, installed software, etc. with no issues. Now all of a sudden, the DVD drive nor the USB boot options are showing up while booting nor in BIOS; just the HD is available. Oddly, if I boot into Windows the USB drives and the DVD drive show up in Windows Explorer & function fine. I was going to install the OS yet again but I'm hesitant due to the BIOS not showing the DVD/USB options. Here are some of the things I tried:

• Reset CMOS - no dice
• Disconnected HD - no boot devices found
• Switched HD & DVD SATA cables - no dice
• Updated BIOS firmware to latest available version - no dice
• Updated all drivers (including chipset) to latest version via Gateway support site
• Replaced RAM module

Any help is appreciated!

 

In the bios turn off secure boot and enable csm or legacy. You may have to use <shift> 'restart' to enable getting into using 'boot from usb' option.