The unit is blinking red indicating "the firmware is corrupt. See the User Manual for instructions." However the user manual makes no further reference to the issue.
Is anyone able to point me in the direction of what to do?
and here's a video walk through using a tftp client. Use the built in one for windows 10 though. the video is more of an example of how its done. https://www.youtube.com/watch?v=R9DLrLQrpaw
The device I can still connect to the internet on is a Mac as I was using the WNCE4004 to connect to my PC
That is an old (2012) device that Netgear no longer makes.
What was the WNCE4004 doing in the connection to your PC?
It was intended to provide a wifi to wired-Ethernet connection to things. These days you have several options. For example, you could replace the WNCE4004 with a wifi extender. Another option would be to use Powerline Ethernet to wire the PC to the router over the mains circuit.
This is guesswork on my part based on knowing next to nothing about the router you have and what else is on your network.
The PC was one provided by my work which was never intended to be used outside the office, so has no wi-fi. Since Covid it has been used at home. As I was already using the WNCE4004 to provide ethernet connection to some Hi-Fi equipment to provide internet radio, it seemed like the simplest solution at the time, especially as any PC equipment for working from home was in short supply.
I've seen that some current Wi-Fi extenders also have ethernet outputs, so I'll look into those
