Well folks, I finally found a solution for the BIOS update.I downgraded to version 2.5.1 and then installed version 2.8.0.It worked.
I am having two problems with this machine:1-Every time I have to install the new BIOS, an error occurs. Either via Windows or via BIOS. It won't install at all. 2-The Waves Maxx Audio app again stopped working and even uninstalling and installing it doesn't work. Anyone going through these difficulties or that passed and solved it? Thanks.
XPS 8940, no update to BIOS 2.7.0