There is a problem with DHCP.
When your computer starts it broadcasts to get an ip address via DHCP. If it fails to receive an adddress automatically, it will make one up starting with 169..
Go into your router and make sure the DHCP is turned on, and with the correct range i.e. 192.168.0.2 - 192.168.0.254.
If you can't sort it, then just statically asign addresses to all your computers.