Reboot toggles networking

[corkie]

I have a problem getting my wired network to connect every second time I start mint.
If the connection isn't there when I boot up I just restart and there it is. If I reboot when it is working that kills it.
Can anyone suggest what services I might check to see if i can restart networking without resorting to a reboot.
I'm currently on mint 19. It was like this on mint 18 as well.
The offending machine is a win7 Toshiba satellite laptop which I am dual booting with mint. It used to have wifi but the wireless modem overheated and died one day and I couldn't get any of the replacements to work. Not sure if that was a hardware or a driver issue.

[adamwbb]

Hey does the output of inxi between reboots show the network adapter appearing and dissappearing

[corkie]

Thanks for that. I'd never heard of inxi before so I had a good play with it last night.
Tonight I am testing the target computer.

Yes This is what comes up when things are working:

corkie@corkie-Satellite-C660 ~ $ inxi -n
Network: Card-1: Realtek RTL8101/2/6E PCIE Fast/Gigabit Ethernet controller
driver: r8169
IF: enp1s0 state: up speed: 100 Mbps duplex: full
mac: 00000000
Card-2: Intel Centrino Advanced-N 6235 driver: iwlwifi
IF: wlp6s0 state: down mac: 0000000000

corkie@corkie-Satellite-C660 ~ $ inxi -N
Network: Card-1: Realtek RTL8101/2/6E PCIE Fast/Gigabit Ethernet controller
driver: r8169
Card-2: Intel Centrino Advanced-N 6235 driver: iwlwifi

But every second boot we have this:

corkie@corkie-Satellite-C660 ~ $ inxi -n
Network: Card: Intel Centrino Advanced-N 6235 driver: iwlwifi
IF: wlp6s0 state: down mac:00000000000

Interesting that my non working wifi card is there all the time. But the ethernet card comes and goes.

Does some one know what this means?