PC boot minor issue/question

Twice recently my PC has had an odd cold boot up. What happens is that I get a black screen with only the mouse pointer visible for 10 or 15 seconds, and then Windows (Vista in this case) kicks in and everything proceeds normally from there. Most of the time this doesn’t happen, but I’m a bit concerned as to what is causing this issue. Malware/Spyware/etc. all are up to date and show nothing when scans are run and I’m not running all that much at startup.

Is there any log or anything that would tell me what was going on during this event?

It’s probably just an update finishing its intallation. Happens to me from time to time. You can enable boot logging from you system configuration menu, which will create a file called ntbtlog.txt in your root drive.

When it’s a black screen with a cursor, on the other hand, I believe that means that your OS is up and running but cutting off accessibility while it’s finishing a process (normally an update). With that in mind, you may be able to find out in the even viewer.