I have to be honest and say that wifi for me worked seamlessly right out of the box. Connected first time and has been nothing but stable. Im using XP home and a generic router supplied by my ISP.
So from the sound of it you can get connected but not reliably? So there is no point going through how to connect as I guess you are up to speed on that.
I guess it could just be faulty? One option could be return and replace? Hassle I know – but if you really like it.
Perhaps some others here might have some tips!