Hit F2 at power-on to get into the BIOS. This describes itself as Phoenix TrustedCore(tm) Setup Utility.
The Boot screen shows a list of whatever bootable items it finds. There is space for 8 entries. As usual these can be ordered by highlighting the one of interest and then using the + and - keys to move it up or down the order.
There is also a section at the bottom of items that are specifically excluded from the boot order.
In my case with a Compact Flash card fitted and a pen drive plugged in to a USB port, the screen showed:
1 : PCI BEV: Realtek PXE B08 D00 2 : IDE 0: FTS1GCF80-(PM) 3 : USB KEY: USB2.0 FlashDisk-(USB 2.0(R/F)F 4 : 5 : 6 : 7 : 8 : Excluded from boot order: Legacy Network Card Bootable Add-in Cards
You can also get straight to these options by hitting the F12 key.
The S450-2 runs eLux RL.
Any comments? email me. Added January 2019