Hello and welcome to Bleepingcomputer.
I read about your problem above.
When a BIOS rom chip is flashed it re-writes the firmware in the EEPROM, whether a device is present or not during the flash, does not matter, because the BIOS was not written according to what is presently installed, it was written to accommodate the addition of other hardware to the system.
So with that being said, it should not matter if the floppy drive was present when the BIOS EEPROM was flashed.
An EEPROM (Electrically Erasable Programmable Read Only Memory) is a Flash ROM type chip, the code is written to accept the addition of new hardware at any time regardless of what was in the system when a flash was last done.
What you should be concentrating on here, is making sure the 40 or 80 flat ribbon wire data cable is plugged in at both the motherboard and at the drive's sockets.
Make sure the flat data cable for the floppy is plugged in correctly.
Upon booting the computer enter the BIOS setup utility, I believe yours is entered by pressing F2 at boot up.
You should now be in the BIOS setup utility, now depending on how your menus are setup, you should see than area related to hardware, Dell's BIOS setup utility has (in my history) been setup in several different ways on several different Dell computers, but you should be looking for hardware, such as Floppy and Drives.
Once you enable the devices, you have to save the changes, on some Dell computers you have to enable those devices in each menu, by high-lighting the word enabled and making sure that upon exiting the BIOS setup utility, the changes have been saved.
What is making it difficult for me to give concise directions to you is because Dell has used different methods of how the BIOS menus are arranged on their older computers.
Some BIOSes list every thing in MAIN menus in a list going from the top to bottom of the screen and you have to expand each of them from there, some list everything in a main menu at the top of the screen going from left to right and the list of settings running down each menus' screen.
Edited by MrBruce1959, 19 July 2010 - 12:35 PM.