After I installed Vista SP1, I noticed two entries in the event viewer after
every boot

Event ID 46 Volmgr Event ID 46 Crash Dump Initialization failed!

I noticed quite a few people have this problem. Here was my solution.

Goto Control Panel\System and Maintenance\System
Click on "Advanced System Settings" on the left panel
Under "Startup and Recovery" select "Settings"
Make sure you have a check mark beside "Write and event to the system log"

I always disabled these settings on XP and Vista before SP1, but it appears
this causes the above error message after Vista SP1 is installed.
This worked for me, I hope it helps somebody else.