I disable any boot block settings in the bios, plus windows firewalls before flashing. The dell bios may not have any bios protection settings; you'll just have to check. Why are you flashing the bios? Are you sure the new file will fix any issues? Most oem bios updates don't give you the option of new generation cpus, such as going from the old smithfield core to wolfdale core2 duos. If you keep having problems, it may be a blessing in discuise.