According to apple history, the Powerbook 190cs requires a minimum of System 7.5.2 which means the System 7.5 on Apple's Network Access Disk will not boot your machine without an Enabler. And in further reading you need both a 7.5.2 System file with a Powerbook 5300/2300/190 Enabler, neither of which I could find on the Internet. Even if you had those, it would take someone fairly knowledgable to replace the System file and fit the enabler on a 1.44mb disk.