when i first want to connect to the internet via my wifi laptop,the system asks for diagnosis which gives message "switch on wireless capapbility,how do you get the computer to do this automatically.I am running vista premium
Not sure exactly what you mean ....
but generally wifi is controlled with a physical on / off switch somewhere on the lappy
when it's on ... xp or vista (in your case) will try to connect through it (or whatever other network connection it finds working).
generally vista is very good (better that XP) at finding a network
but
if nuffin is connected .... nuffin 'appens