WiFi extender Failure

I tried using a netgear wifi extender last year, but it was such a failure as the signal continually dropped out making it useless.

Anyway, this year I am adding a wired extension to my network, using a LAN switch and cables (obviously!).  That is so I can use other PCs in areas where the WiFi does not reach.  However, I still want to use WiFi on phones etc in thos areas so I thought I'd give the netgear range extender another try.

I plugged it into the LAN switch (assuming that, if I was only extending wifi from THAT point, the signal may not drop off so easilly) and it lit up to go, but here's the issue:  When the extender is plugged into the LAN switch, the wired connection from the switch to other PCs drops out.

Anyone got any bright ideas?

Obviously I've considered the whole smashing the netgear extender with a lump hammer.