Here is another Vista feature. I was having trouble with my internet connection, so I rebooted my PC. During the boot process I received this error message: Windows could not connect to the System Event Notification Service service. My PC finishes booting and my wireless network connection is down and cannot be brought back up.
Fortunately, judging from the number of hits when performing a google search, the problem and fix are well known. I will repeat the fix here.
1) Start -> All Programs -> Accessories (folder) -> Command Prompt
2) Right Mouse Click on Command Prompt and select Run as Administrator
3) At the command prompt enter: NETSH WINSOCK RESET CATALOG
4) Hit return
5) Reboot computer.
For more information, check out these links: http://carbonize.co.uk/wp/2009/02/15/system-event-notification-service-not-starting-on-vista/ and http://www.physicsforums.com/showthread.php?t=313388