copy the content of a message from event viewer, then search the Microsoft support site and Google. But, don't be surprised to find that 99% of these messages are benign.

If security is a concern, watch your firewall log instead. that's where the real action is. Also, be sure to use a router with a hardware firewall, too. If you want to keep people out, your 1st line of defense is a router with hardware firewall (readily available). Next, the software firewall, such as the one that comes with Vista. Be sure to have good anti-virus and anti-spyware software installed. Then, and a lot of people neglect this, be sure to keep your software up to date. Let Vista and your other security apps manage their auto-update process.

Finally, practice what some call "skeptical computing". See http://arstechnica.com/articles/paedia/malware.ars/1 for an overview.

In my years of computer use and computer support, I really only worry about event viewer if I need to diagnose a problem. That's when those cryptic messages can have a LOT of value. Otherwise, I'm worried you might be focusing on the wrong thing.