Vista just repaired itself, where the log @

[XDanger]

PC wouldn't load windows, Just kept swiping the bar with no usual pause so I put the vista disk in and let it repair

How can I find out what caused it?

[CaptNKILL]

I don't know if a repair install clears out the Event Viewer logs, but it might be in there.

Go to the control panel: administrative tools: event viewer

I'm not sure where it'd be but if its there it shouldn't be too hard to find.

[Wolfhound]

You can use Windows debugging tools:

http://www.microsoft.com/whdc/devtools/debugging/default.mspx

and Performance Analizer:

http://msdn.microsoft.com/en-us/library/cc305187.aspx

This are the 2 apps I use to debug all my Windows systems at home and at work ;)