Where exactly are you stuck? Are you installing Windows onto this new blank 250GB drive? Are you having problems with the floppy drive after you installed this new hard disk?

At a guess are you stuck at the "F6" prompt for additional storage drivers during Windows setup?

Device Manager will only tell you a device isn't working if Windows couldn't load the driver for it - Device Manager neither knows nor cares if the device works properly.

New floppy disks are crap and desperately unreliable, and so is Windows' ability to write to them properly. Windows never did deal with floppies properly. An old machine with DOS and a reliable floppy drive (they don't make em like they used to) is a Godsend when working with floppies.

If your BIOS can access a USB device at boot time (ie, before Windows loads), you might be able to format a USB flash drive on another machine, and copy the drivers to that, then use that instead of the floppy disk as the BIOS will emulate drive A: with the flash drive (leave the USB flash drive connected to a USB port before and throughout Windows Setup).