WiFi Trouble with Windows Vista Business

I have two computers side bi side my old laptop is running window XP pro and
the wifi connection works fine, my other tablet that I just upgraded to Vista
Business looses the connection and then will not reconnect? My older pc with
XP will lose the connection also but will then reconnect when the signal is
back, I am on a public wifi network at my school where I live. I don't
understand how to set up Vista so it will automatically reconnect when the
signal is back? Vista seems alot more complicated then XP and does not work
as well as far as the WiFi, any ideas? Where can I get some info on how to
set up profile? I am just lost on this one.
thanks Bill