reset network manager such that pc to pc ethernet connection works again

[ubto66]

network manager applet 1.8.20

pc1 has a vpn wifi card internet connection. Network manager ethernet connection ipv4 settings
are shared to other computers. Connecting pc2 by crossover lan cable
to pc1 worked, such that pc2 got internet connection. Then
lanshare
https://github.com/abdularis/LAN-Share/releases
got installed on pc1 and pc2. Did not work and lanshare got uninstalled on both pc1
and pc2. lanshare likely corrupted the network manager. Because now the ethernet ipv4 share with
other computers on pc1 does not work. pc2 cannot connect to pc1 by ethernet. How can you
reset pc1's network manager, such that the network manager appears like when new
installed?
Thanks.