Yes, I'm aware of that. It's where I started from.

When I first bought the router, I had someone set it up for me. He must have used WEP security so the password he gave me did not work (see OP). This meant that I was unable to add new computers to the wifi network. I eventually bought some homeplug units which work very well giving a wired network round the house, but we wished to connect some computers wirelessly, so I eventually bit the bullet, reset to factory settings and started again. If you look further up the thread, you will see I have the wifi working again.