BIOS update using boot CD

[#1]

I've got a Dell Inspiron 6400 and the BIOS update file from Dell doesn't work.  Dell forums say I should update the BIOS using a boot CD and the update file from Dell.  The trouble is I managed to burn a boot CD but when the laptop booted into DOS I couldn't find the BIOS file on the CD to run the update.  Can anyone explain how to create a boot disk and what I need to do once it boots the laptop?  Thanks,  Cliff.

[#2]

LINK
Which bios update have you got as the one above you run from within windows?
You need to know what the update runs on as if you boot to dos and its a windows programe it wont work.

[#3]

LINK
This is the link to the update file.  When I download the file and then close everything and double click the file I get a windows error code which is not helpful at all.

[#4]

It should just run from windows but there is a dos applications as well. What error do you get its worth contacting dell as the may have a solution