Hi,
Very good! OK, so now you have a fresh, fully working System 7.5.3 on the PowerBook 190cs.
If one does not want a mere change of a previously installed system folder, it is possible to perform a Clean Installation (see steps 7 and 8 in article TA44452 below; disregard the information about 7.5.5).
http://support.apple.com/kb/TA44452
As Jeff indicated, in order to reformat/erase the internal hard drive, a bootable tools floppy is normally required. You could create a suitable Disk Tools floppy (the downloadable Disk Tools PPC is OK for this purpose) on the now working PowerBook 190cs to begin with. Create the sector-copied floppy via the Make a Floppy command (under the Utilities menu) of Disk Copy 6.3.3.
http://download.info.apple.com/Apple_Support_Area/Apple_Software_Updates/English -North_American/Macintosh/System/Mac_OS_8.1_Update/
http://download.info.apple.com/Apple_Support_Area/Apple_Software_Updates/English -North_American/Macintosh/Utilities/Disk_Copy/
Once the PowerBook 190cs has started from a bootable floppy disk, it is possible to drag-copy the system folder of the floppy onto an empty hard disk. This would create a temporary system folder on the hard disk, leaving the floppy drive free for subsequent transfers.
However, if transfers involve PC-formatted floppy disks, it is also necessary to have a PC Exchange control panel in the system folder. Therefore it may be wise to make a backup copy from the existing system of said control panel on a Mac-formatted floppy disk; the control panel could then be re-introduced into a temporary system folder).
It would be much easier to buy an inexpensive PC Card (PCMCIA) adapter for CompactFlash, and a small CompactFlash memory card. Insert the adapter with the CompactFlash card in one of the PC Card slots of the PowerBook 190cs. Reformat the CompactFlash card to Macintosh (HFS/Standard). Then either use the System 7.5.3 installer to install a system folder on the CompactFlash card, or just drag-copy the entire existing System 7.5.3 folder from the hard disk to the CompactFlash card. After this, it should be possible to boot the PowerBook 190cs from the CompactFlash card (do also check the Startup Disk control panel settings).
Various disk utilities can be installed on the CompactFlash card (such as Drive Setup 1.7.3).
http://download.info.apple.com/Apple_Support_Area/Apple_Software_Updates/English -North_American/Macintosh/Utilities/Drive_Setup/
One can also place the nineteen decoded System 7.5.3 files in one common folder on the CompactFlash card, allowing installations to be carried out from there.
Jan