I remember that problem! It's actually fairly common on Vista, but I must say, I haven't seen it on Windows 7 yet.
Are you also experiencing this problem in Safe Mode with Networking?
Oh, and do you, by any chance, use ZoneAlarm? If so, re install it will quite possibly solve your issue.
From what I know, there were little to no fixes in Vista besides upgrading to 7..
Good luck and keep us posted!