I was having a problem with Gtalk client on my Windows 7 64 bits machine. The problem was that Gtalk got hanged when someone send the message while the gtalk client is in inactivated mode. The solution for that problem is that you need to disable the notification (esp: Play Sound) in Gtalk Setting. Some said that disabling “Play Sound” for incoming chat or call does the trick but I disabled all notifications since I don’t need them. I hope you find it useful.