Vista doesn't sleep - how do I diagnose?

Here is an interesting troubleshooter for Vista sleep problems. Scroll down the website for the steps.

"I had a similar issue before too - Vista machine simply would not sleep.

The best place to look for information would be the Event Viewer tool.

Start > Run > eventvwr.msc

under ""System"" you should find some errors that gives clues as to what is stopping the system from sleeping - in my case it was my wireless drivers. Updated them and was perfectly fine after that.

So, use Event Viewer as a stepping board to narrow your troubleshooting scope, it's really useful."