Upgraded From Antivirus 2008 To 2010 And It Now It Won't Download Updates...

I downloaded and installed antivirus 2010 over antivirus 2008 in Vista-32bit today. It registered fine with my key, but when I went to update the software, the auto update window just hangs at 0% forever like it can't connect to the internet. 2008 was working find and my internet connection is definatly working. Any idea on what went wrong? Thanks.