I have an old laptop ffrom 2008 incould try but other than that my desktop is the only pther windows machine in my household, ill try the laptop
Just as a long shot, connect the powerline adaptor to a different EThernet port on the hub. If that doesn't work, it would appear that the fault lies with the PLAs.
So obviously not a problem with the PC.
Carry out some more diagnostics.
Move the slave adaptor down stairs and plug it in there and see if you can access the Internet on the laptop.
I assume If you did reset the powerline adapters to factory settings did you then re-pair them before using?
"The default gateway is not available" suggests the powerline is not getting through to the router.
Stupid question: is the powerline adapter at the other end connected to an ethernet port on the hub?
I have a similar setup for my PC using a Devolo powerline - works just fine.