New
#11
Do you have a wireless connection on this system? They would not normally come as standard for a desktop. If not see if you can borrow a USB Wi-Fi dongle to check if the signal is usable upstairs. (My Main Router is available in my car parked about 50m from the unit, but coverage is dependent on many things
With your set-up the wireless route may be the best way to proceed.
It's also possible to use something like power-line adaptors as I previously suggested, or purchase and run an Ethernet cable upstairs.
These could either allow direct connection to your system or to run the Netgear Nighthawkas a remote router local to your system and give wireless signal upstairs with the PlusNet Router providing Wi-Fi services on the ground floor.