ok, here's the deal... I got my new Vista on Vaio and faced the same problem... thanks to a friend, we could solve it out.
it seems (for some weird reason) that vista acknowledges the same wireless network more than once, and registers it in a numbered manner; like if your wireless network name is wifi, you'll find it registered in the list of wireless networks as wifi1, wifi2, wifi3 ... and so on.
what we had to do at some point is delete all unused wireless networks, and merge all instances of the currently used networks into one; and this (I happily announce) solved it
so, to do so, please go to Control Panel > Network and Sharing Center > at the current wireless network click on Customize > Merge or delete network locations > Continue. the Merger or Delete Network Locations will appear; try to delete all network locations that are not currently used (maybe you should delete all but the one you are currently trying to connect to), if you have more than one instance of the same location you are trying to connect to (e.g wifi, wifi1, wifi2 ...); select them all and click on Merge. Merge Network Locations Window will pop up, select the network location you're going to merge to (Wifi) and then OK > Close > Next > Close
you should be able to browse now.... hope it works