Prob flash 5100ato 5500a



i ran 1.51 frimware windows flasher to enable my nec nd5100a to read dvd my dvd drive will now not read any disks and i would really appreciate some guidance to rectify this or maybe revert to the dvd factory settings.
i looked at neroinfo tool and it is now recognising my dvd as a 5500a version 1.51 as expected but will not read anything. please help!
thank u