I don't know what you are referring to by "device list in the BIOS"
Does the startup disk you made work correctl in your working computer? (Do you get a menu asking to boot with or without cd-rom support and eventually arrive at an a:\> prompt)?
When you use it in the faulty system, what exactly happens? Does the floppy drive light up and try to run? Any error messages?
If nothing happens, you may not have the BIOS configured correctly? To enter the BIOS, you must press a particular key, often DEL at the startup. Then you will see a set of configuration pages, one of which will list the boot order. The a:\ drive must be first for the floppy drive to work. Sometimes you can set the cd-rom drive first and be able to use that to reload windows.
Sometimes renaming win.com will overcome the above error.
From a command prompt: ren c:\windows\win.com win.old
BIOS For Different Motherboards
Press Tab during boot=Emachine
Press del during boot= (AMI, Award).
Press Esc during boot= Toshiba.
Press F1 during boot= (Toshiba; Phoenix; Late model PS/1 Value Point and 330s).
Press F2 during boot = (NEC).
Press F10 when square in top RH corner of screen= (Compaq).
Press Ins during boot=IBM PS/2 with reference partition.
Shift Ctrl Alt + Num Pad del= - Olivetti PC Pro.
Ctrl Alt ? =some PS/2s, such as 75 and 90.
Ctrl-Esc = Misc Puters
Ctrl Ins= some PS/2s when pointer at top right of screen.
Press reset twice= some Dells.
Ctrl Alt Enter= Dell.
Ctrl Alt Esc=AST Advantage, Award, Tandon.
Ctrl Alt + =Misc Puters
Ctrl Alt S= Phoenix.
Ctrl Alt Ins= (Zenith, Phoenix)
Ctrl S =(Phoenix).
Ctrl Shift Esc= Tandon 386.