If you get errors 161 and 163 at boot, followed by an invitation to press the F1 key, that means the CMOS battery is flat and needs to be replaced.
If you proceed with the system boot anyway by pressing the F1 key, you’ll quickly discover that the floppy drive can’t read floppy disks. This is probably not due to a floppy drive malfunction, but to the missing floppy configuration in the CMOS memory.
First of all replace the battery and then run the CONFIGUR.EXE program that should be present in the C:\DOS directory.
For a guide on how to replace the battery see CMOS battery replacement
If after the battery replacement and the CMOS reconfiguration the floppy drive still doesn’t work, then proceed to replace it. See the Floppy drive replacement how-to for a cheap solution.