This is not an incorrect file issue, this is either a bad EEPROM or an incompatible programmer. If the programming and the chip were actually doing their job, it should start writing the data from 0000000 until 0027FFF, there is no data in there though... The only data I've found as at the end of the read
E5 20 F1 FF FF FF FF 01 44 EB 08 6B 08 3B 80 BB
EE FF FF FF FF FF 00 00 FF FF 00 00 0C 20 0F 52
10 D8 00 00 FF FF FF FF FF FF FF FF FF FF FF FF
Which I have tried matching to the BIOS file and no such data exists in the BIOS file, regardless if I make you a 4MB file and set the unused bytes as "FF", it's going to be useless because the programmer or your EEPROM is not writing properly to the chip. Let's also not forget that the BIOS just "disappeared", which makes the EEPROM sound at fault even though it is being detected.
Once the programmer can write successfully to the EEPROM, then we can talk about it not being a 4MB BIOS file, this is just like trying a 240v ONLY appliance in a 120v country and being surprised that its not turning on and you'd attempt to fix it, the first correct step would be to get a 240v up converter and try it there, because until you gave the thing 240v you won't know for sure if it works or not.
So, here You are: Corrupted BIOS file (4MB) http://speedy.sh/vX75Q/Corrupted-Dell-Vostro-470-bios.bin
Chip and programmer are 100% fine