Computer not recognising my wifi but does see the neighbours'

[olympus]

Thanks for all the advice guys. I should have said that I went through the routine of powering-down the router and the computer(s) then powering-up again yesterday (a Google search suggested that) but without any success.

Following advice today, I placed the laptop next to the problem machine and yes, it's connecting to the internet perfectly so I guess the signal strength is OK. I did try uninstalling the network card in Device Manager and then re-installing the drivers when Windows recognised it on re-start with no noticeable change except it's now recognising more of my neighbours' networks but still not mine!