Hot spot log in will not come up

I recently purchased a dell 1520 inspiron laptop and I have been having problems getting it to work at a hot spot.  I have no problem connecting to the hot spot's unsecured network but the log in screen that is suppose to come up in my browser will not come up. 

 

 A friend of mine can connect no problem with her laptop running xp but it seems maybe some setting in vista may be causing a problem. 

 

The sites tech support ran me through a number of potential fixes but no luck.

 

I can connect wirelessly to  my wireless router at home no problem at all, but of course theres no need for a log in screen to pop up, just the encryption key, and once connected at home I can access the internet no problem.

 

my wireless card is: Dell wireless 1490 dual band wlan mini-card rev 5.8

 

So does anyone have any idea why the "walled garden" (log in screen) will not come up when I open my browser even though I am connected to the network?